NATIONAL LIBRARY OF MEDICINE Bethesda, Maryland
V
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EXPLANATIONS.
//Jo EXPLANATIONS
A SEQUEL TO - /
VESTIGES OF THE NATURAL HISTORY OF CREATION."
BY THE AUTHOR OF THAT WORK.
8r Sir Richard Wr*M
NEW YORK: WILEY & PUTNAM, 16] BROADWAY. 1846.
CONTENTS.
PAGE
Design of the Vestiges explained 2
Proper Position of the Nebular Hypothesis in the Argument. . 3 Imputed Failure of the Hypothesis from the Earl of Rosse's
discoveries, denied 6
Experiments illustrating and confirming the Hypothesis by
Professor Plateau 10
Objection from the retrogression of Uranus's Satellites consi- dered 13
Objection respecting the convergence of atoms to a central
nucleus, answered 14
The Nebular Hypothesis not a supersession of Deity, but only a
description of his mode of working 16
Quetelet's inquiries, establishing law in mental operations. ... 17
Limits of the syslem being under law, the whole is probably so 18
Question of the Origin of Organic nature 19
Geology proves it to have observed a progress in time 21
Objections respecting this progress 22
Lower Silurian Fossils 23
Upper Silurian Fossils 33
Old Red Sandstone 34
Carboniferous System 42
Permian System 45
Outline of the Genetic Plan of the Animal Kingdom 49
Bearing of this Plan on the Arguments of Objectors 53
Reptiles of the Muschelkalk, Lias, &c 58
Objections as to first Footmarks of Birds 60
Vi CONTENTS.
PAGE
Objections as to Earliest Mammalia 62
Tertiary Formation 64
Opinions of Cuvier and Agassiz 70
Apology of Mr. Sedgwick for Over- Ardent Generalizations. . . 71
Physiological Objections of Dr. Clark, of Cambridge 73
Views of others respecting Embryotic Development 75
Germs not alleged to be identical 77
Transmutation of Plants 78
Species a Term, not a Fact 80
Instances of Transmutation 81
Transmutation does not imply extinction of Elder Species. ... 83
The Broomfield Experiment 84
Proof of Aboriginal Life in the present era not essential to the
theory of Organic Creation by Law 86
The Opposite Theory characterized 88
Views of Dr. Whewell, and objections to them 90
Views of the Edinburgh Reviewer — these analyzed 95
Views of Professor Agassiz 99
Views of Sir John Herschel 100
Support to Theory of Law from Rev. Dr. Pye Smith and Black- wood's Magazine 101
Mr. Stuart Mill on Universal Causation 102
Present State of Opinion on the Origin of Organic Nature
examined 105
Animals have not come immediately on the occurrence of proper
conditions 207
Great number of distinct Floras 107
Supposed Formation of New Species, as upheld by Professor
Owen, &c, inadmissible 108
Opinions of Professor Pictet on Peculiarity of Species in each
formation HO
Time the true key to difficulties arising from apparent per- manency of species HI
Vast spaces of time involved in the Geological record 112
Zoology of Galapagos Islands, an instance of comparatively re- cent development 114
Author's theory supported by facts connected with the distri- bution of plants 117
CONTENTS. Vii
PAGE
Whence the iirst impulse to vitality? 119
The Vestiges— its object purely scientific— defended on this
ground m
Ungenerous policy of Geological Objectors 120
Opposition of the Scientific Class 123
Estimate of this Opposition 124
Utility of Hypotheses 127
Bearing of the new doctrine on Human Interests 129
Its Moral Results 130
Consolations and Encouragements offered by it 132
Appendix— Letters of Mr. Weekes on Aboriginal Production of Insects 134
EXPLANATIONS.
When the work to which this may be regarded as a sup- plement was published, my design was not only to be per- sonally removed from all praise or censure which it might evoke, but to write no more upon the subject. I said to myself, Let this book go forth to be received as truth, or to provoke others to a controversy which may result in establishing or overthrowing it ; but be my task now ended. I did not then reflect that, even though written by one better informed or more skilled in argument than I can pretend to be, it might leave the subject in such a condition that the author should have to regret seeing it in a great measure misapprehended in its general scope, and also so much excepted to, justly and unjustly, on par- ticular points, that ordinary readers might be ready to suppose its whole indications disproved. Had I bethought me of such possible results, I might have announced, from the beginning, my readiness to enter upon such explana- tions of points objected to, and such reinforcements of the general argument, as might promise to be serviceable. And this would have seemed the more necessary, in as far as it may be expected that there are many points in a new and startling hypothesis which no one can be so well qualified to clear up and strengthen as its author. I might 2
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have felt, at the same time, that a new adventure, for whatever purpose, in the same field, was hazardous, with regard to any favorable impression previously produced ; yet such an objection would, again, have been at once overruled, seeing that public favor and disfavor were alike beyond the regard of an author who bore no bodily shape in the eyes of his fellow-countrymen, and was likely to remain for ever unknown. Such reflections now occur to me, and I am consequently induced to take up the pen for the purpose of endeavoring to make good what is deficient, and reasserting and confirming whatever has been un- justly challenged in my book. In doing so, I shall study to direct attention solely to fact and argument, or what appear as such, overlooking the uncivil expressions which the work has drawn forth in various quarters, and which, of course, can only be a discredit to their authors.
I must start with a more explicit statement of the gene- ral argument of the Vestiges, for this has been extensively misunderstood. The book is not primarily designed, as many have intimated in their criticisms, and as the title might be thought partly to imply, to establish a new theory respecting the origin of animated nature ; nor are the chief arguments directed to that point. The object is one to which the idea of an organic creation in the manner of natural law is only subordinate and ministrative, as like- wise are the nebular hypothesis and the doctrine of a fixed natural order in mind and morals. This purpose is to show that the whole revelation of the works of God pre- sented to our senses and reason is a system based in what we are compelled, for want of a better term, to call law ; by which, however, is not meant a system independent or exclusive of Deity, but one which only proposes a certain
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mode of his working. The nature and bearing of this doc- trine will be afterwards adverted to ; let me, meanwhile, observe, that it has long been pointed to by science, though hardly anywhere broadly and fully contemplated. And this was scarcely to be wondered at, since, while the whole physical arrangements of the universe were placed under taw by the discoveries of Kepler and Newton, there was still such a mysterious conception of the origin of organic nature, and of the character of our own fitful being, that men were almost forced to make at least large exceptions from any proposed plan of universal order. What makes the case now somewhat different is, that of late years we have attained much additional knowledge of nature, point- ing in the same direction as the physical arrangements of the world. The time seems to have come when it is pro- per to enter into a re-examination of the whole subject, in order to ascertain whether, in what we actually know, there is most evidence in favor of an entire or a partial system of fixed order. When led to make this inquiry for myself, I soon became convinced that the idea of any ex- ception to the plan of law stood upon a narrow, and con- stantly narrowing foundation, depending, indeed, on a few difficulties or obscurities, rather than objections, which were certain soon to be swept away by the advancing tide of knowledge. It appeared, at the same time, that there was a want in the state of philosophy amongst us, of an impulse in the direction of the consideration of this theory, so as to bring its difficulties the sooner to a bearing in the one way or the other ; and hence it was that I presumed to enter the field.
My starting point was a statement of the arrangements of the bodies of space, with a hypothesis respecting the
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mode in which those arrangements had been effected. It is a mistake to suppose this (nebular) hypothesis essential, as the basis of the entire system of nature developed in my book. That basis lies in the material laws found to prevail throughout the universe, which explain why the masses of space are globular ; why planets revolve round suns in elliptical orbits ; how their rates of speed are high in proportion to their nearness to the centre of attraction ; and so forth. In these laws arises the first powerful pre- sumption that the formation and arrangements of the celes- tial bodies were brought about by the Divine will, acting in the manner of a freed order or law, instead of any mode which we conceive of as more arbitrary. It is a presump- tion which an enlightened mind is altogether unable to re- sist, when it sees that precisely similar effects are every day produced by law on a small scale, as when a drop of water spherifies, when the revolving hoop bulges out in the plane of its equator, and the sling, swung round in the hand, increases in speed as the string is shortened. The philosopher, on observing these phenomena, and finding incontestable proof that they are precisely of the same nature as those attending the formation and arrangement of worlds, learns his first great lesson — that the natural laws work on the minutest and the grandest scale indiffer- ently ; that, in fact, there is no such thing as great and small in nature, but world spaces are as a hair-breadth, and a thousand years as one day. Having thus all but demonstration that the spheres were formed and arranged by natural law, the nebular hypothesis becomes important, as shadowing forth the process by which matter was so transformed from a previous condition, but it is nothing more ; and, though it were utterly disproved, the evidence
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which we previously possessed that physical creation, so to speak, was effected by means of, or in the manner of law, would remain exactly as it was. We should only be left in the dark with regard to the previous condition of matter, and the steps of the process by which it acquired its present forms.
It would nevertheless strengthen the presumption, and, indeed, place it near to ascertained truths, if we were to obtain strong evidence for what has hitherto been called the nebular hypothesis. The evidence for it is sketched in the Vestiges : it is exhibited with greater clearness, and in elegant and impressive language, in Professor Nichol's Views of the Architecture of the Heavens. The position held by this hypothesis in the philosophical world when my book was written, is shown, with tolerable distinctness, in the Edinburgh Review for 1838, where it is spoken of in the following general terms : — " These views of the origin and destiny of the various system of worlds which fill the immensity of space, break upon the mind with all the inte- rest of novelty, and all the brightness of truth. Appealing to our imagination by their grandeur, and to our reason by the severe jmnciples on which they rest, the mind feels as if a revelation had been vouchsafed to it of the past and future history of the universe." It may also be remarked that this writer considered the hypothesis as " confirming, rather than opposing the Mosaic cosmogony, whether alle- gorically or literally interpreted." With this testimony to the mathematical expositions of MM. La Place and Comte, I rest content, as the expositions themselves would be un- suitable in a popular treatise. But the hypothesis has been favorably entertained in many authoritative quarters, dur- ing the last few years, and probably would have continued
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to be so, if no attempt had been made to enforce by it a system of nature on the principle of universal order.
The chief objection taken to the theory is, that the ex- istence of nebulous matter in the heavens is disproved by the discoveries made by the Earl of Rosse's telescope. By this wondrous tube, we are told, it is shown to be " an unwarrantable assumption that there are in the heavenly spaces any masses of matter different from solid bodies composing planetary systems."* The nebulae, in short, are said to be now shown as clusters of stars, rendered apparently nebulous only by the vast distance at which they are placed. There is often seen a greater vehemence and rashness in objecting to, than in presenting hypothe- ses ; and we appear to have here an instance of such hasty counter-generalization. The fact is, that the nebulae were always understood to be of two kinds : 1, nebulae which were only distant clusters, and which yielded, one after another, to the resolving powers of telescopes, as these powers were increased ; 2, nebulae comparatively near, which no increase of telescopic power affected. Two classes of objects wholly different were, from their partial resemblance, recognized by one name, and hence the con- fusion which has arisen upon the subject. The resolution of a great quantity of the first kind of nebulae by Lord Rosse's telescope was of course expected, and it is a fact, though in itself interesting, of no consequence to the ne- bular hypothesis. It will only be in the event of the second class being also resolved, and its being thus shown that there is only one class of nebulae, that the hypothesis will suffer. Such, at least, I conclude to be the sense of a
* North British Review, iii.,477.
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passage which I take leave to transfer, in an abridged form, from a recent edition of Professor Nichol's work.
" I. By far the greater number of the milky streaks, or spots, whose places have hitherto been recorded, lie at the outermost, or nearly at the outermost boundary of the sphere previously reached by our telescopes ; and in this case there is no certain principle on the ground upon which a pure nebula can be distinguished from a cluster so remote that only the general or fused light of its myriads of constituent orbs can be seen. Sometimes, — resting on a pecu- liarity of form or other characteristic, — the astronomer may venture a guess that such an object is probably a firmament; as, indeed, I was bold enough to do in former editions of this work with regard to several which have since been resolved ; but, in the main, he can tell little concerning them, or have any other belief, than that, as with similar masses near him, a great, probably the greater num- ber, are true clusters, grand arrangements of stars, incredibly re- mote, but resembling in all things our own home galaxy. Now, the application to such objects of a new and enlarged power of vision, could be attended only by one result — magnificent, but far from unexpected : and it is here that the six-feet mirror has achieved its earliest triumphs. Under its piercing glance, great numbers of the milky speck3 have unfolded their starry constitu- ents ; some of these, which previously were almost unresolved, shining with a lustre equivalent to that of our brightest orbs to the naked eye. How far it will go with its resolving power has not yet been ascertained ; but I perceive that Sir James South has given his authority that some spots examined by it continue in- tractable.
"II. The influence of the new discoveries either to impair or strengthen the foundations of the nebular hypothesis, must clearly be looked for among their bearings on less remote and ambiguous objects. Now, the new aspects of these may lead us to question our former opinions as to the existence of the supposed filmy self- luminous masses, — or they may throw doubt on the reality of those forms according to which we have arranged them, and which seem to indicate the steps of a stupendous progress.
" 1. Astronomers have never rested their belief in the reality
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EXPLANATIONS.
and wide diffusion of the nebulous matter, on the objects referred to in the first paragraph ; but on others, much within the range of our previous vision. In so far as we have hitherto understood the nature of clusters, the telescopic power required to resolve them is never very much higher than that which first descries them as dim milky spots. But. there are many most remarkable objects which, in this essential feature, are wholly contrasted with clusters. For instance, the nebula in Orion, as I have fully shown in the text, is visible to the naked eye, as also is the gorgeous one in Andromeda; while the largest instrument heretofore turned to them has given no intimation that their light is stellar, but rather the contrary ; although small stars are found buried amidst their mass. Now, if Lord Rosse's telescope resolves these, and others with similar attri- butes, such as some of the streaks among the following plates, we shall thereby be informed that we have generalized too hastily from the character of known firmaments,— that schemes of stellar being exist, infinitely more strange and varied than we had ventured to suppose,— and certainly we shall then hesitate in averring further, concerning the existence or at least the diffusion of the purely nebulous modification of matter.
" 2. Lord Rosse's telescope may also, as I have said, disprove the reality of our arrangement of the forms of the nebulae as steps of a progression. And in regard of this question, there seem two classes of objects meriting attention.
" First, I shall refer to the nebulous stars properly so called, or to that form in which the diffused matter has reached the condition of almost pure fixed stars. Now, of these objects there are two distinct sets, presenting at first to the telescope very much the same appearance, but in regard of which our knowledge is very different. It will readily be conceived that a distant cluster, with strong concentration about the centre of its figure, must, to the telescope which first descries it, look like a star with a halo around it. When a higher power is applied, that central star, however, will appear as a disc, and to a still higher power the cluster will be revealed. A very great number of what are called nebulous stars, are doubtless of this class ; and we have hitherto had no means of accurately ascertaining the fact, just because our largest telescopes were required to descry them ; but there are multitudes
NEBULAR HYPOTHESIS.
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of others — the true ' photospheres ' — quite of a different descrip- tion. Many of these are easily seen as fixed stars with haloes of different sizes diminishing to the mere ' bur and under the great- est power as yet applied, the apparent central star never expands into a disc, or departs from the stellar character. It is by its effect on these that the new instrument will at all bear on this portion of the nebular hypothesis.
" Secondly, The foregoing being our grounds of belief in the existence of nebulae — first, in a diffused or chaotic state, and again in a condition proximate to pure stars ; the only remaining point has reference to nebulae in an intermediate state, — when the round- ish masses seem to have begun a process of organization or concen- tration, and carried it onwards through several stages : a state to which we have every variety of analogon in the various forms and densities of cometic nuclei. Sir William Herschel certainly was not ignorant that round or spherical clusters abound in the skies, which, when first seen, present all the appearances of such nebulae — nay, he grounded on the fact of their approximate sphericity and varying degrees of concentration, some of the boldest and most engrossing of his conjectures ; nor would he have doubted that multitudes which, even to his instruments, seemed only general lights, would, in after times, be resolved ; but here, as before, the gist of the question is not, can you resolve round nebula? never re- solved before ; but can you resolve such as, quite within the range of former vision, have continued intractable under the scrutiny of powers which, judging from the average of our experience, must surpass what ought to have resolved them ?
" Such are my views as to the present condition of this impor- tant question ; and if they are correct, it will appear that, not- withstanding the resolutions achieved by the new instruments, they are, as yet, quite as likely — by accumulating new objects belonging to the three foregoing classes, and by more surely and distinctly establishing their characteristic features— to strengthen, as to in- validate the grounds of the nebular hypothesis. Eagerly, but pa- tiently, let us watch the approaching revelations."
Various minor objections have been presented to the nebular hypothesis ; but, before adverting to any of them,
2*
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I may give a brief abstract of certain recent experiments, by which it has been remarkably illustrated. Here it is peculiarly important to bear in mind, that the phenomena of nature are, if I may so speak, indifferent to the scale on which they act. The dew-drop is, in physics, the pic- ture of a world. Remembering this, we are prepared in some measure, to hear of a Belgian professor imitating the supposed formation and arrangement, of a solar sys- tem, in some of its most essential particulars, on the table of a lecture-room ! The experiments were first conducted by Professor Plateau of Ghent, and afterwards repeated by our own Dr. Faraday.
The following abstract of Professor Plateau's experi- ments is also presented in the fifth edition of the Vestiges. Its being repeated here is, that it may meet the eyes of many who are not likely to see any edition of that work besides those from which it is absent :
Placing a mixture of water and alcohol in a glass box, and therein a small quantity of olive oil, of density pre- cisely equal to the mixture, we have in the latter a liquid mass relieved from the operation of gravity, and free to take the exterior form given by the forces which may act upon it. In point of fact, the oil instantly takes a globular form by virtue of molecular attraction. A vertical axis being introduced through the box, with a small disc upon it, so arranged that its centre is coincident with the centre of the globe of oil, we turn the axis at a slow rate, and thus set the oil sphere into rotation. " We then presently see the sphere flatten at its poles and swell out at its equator, and we thus realize, on a small scale, an effect which is admitted to have taken place in the planets." The spheri- fying forces are of different natures, that of molecular
NEBULAR HYPOTHESIS.
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attraction in the case of the oil, and of universa attrac- tion in that of the planet, but the results are " analogous, if not identical." Quickening the rotation makes the figure more oblately spheroidal. When it comes to be so quick as two or three turns in a second, "the liquid sphere first takes rapidly its maximum of flattening, then becomes hollow above and belosv, around the axis of rota- tion, stretching out continually in a horizontal direction, and finally, abandoning the disc, is transformed into a per- fect/// regular ring." At first this remains connected with the disc by a thin pellicle of oil ; but on the disc being stopped this breaks and disappears, and the ring becomes completely disengaged. The only observable difference between the latter and the ring of Saturn is, that it is rounded, instead of being flattened ; but this is accounted for in a satisfactory way.
A little after the stoppage of the rotatory motion of the disc, the ring of oil, losing its own motion, gathers once more into a sphere. If, however, a smaller disc be used, and its rotation continued after the separation of the ring, rotatory motion and centrifugal force will be generated in the alcoholic fluid, and the oil ring, thus prevented from returning into the globular form, divides itself into " several isolated masses, each of which immediately takes the globular form.''' These are " almost always seen to assume, at the instant of their formation, a movement of rotation upon them- selves— a movement which constantly takes place in the same direction as that of the ring. Moreover, as the ring, at the instant of its rupture, had still a remainder of velocity, the spheres to which it has given birth tend to fly off at a tangent ; but as, on the other side, the disc, turning in the alco- holic liquor, has impressed on this a movement of rotation, the
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spheres are especially carried along by this last movement, and revolve for some time round the disc. Those which revolve at the same time upon themselves, consequently, then present the curious spectacle of planets revolving at the same time on themselves and in their orbits. Finally, another very curious effect is also manifested in these cir- cumstances : besides three or four large spheres into which the ring revolves itself, there are almost always produced one or two very small ones, which may thus be compared to satellites. The experiment which we have thus des- cribed presents, as we see, an image in miniature of the formation of the planets, according to the hypothesis of Laplace, by the rupture of the cosmical rings attributable to the condensation of the solar atmosphere."*
Such illustrations certainly tend to take from the nebular cosmogony the character of a " splendid vision," which one of my critics has applied to it. I may here also remind the reader that there are other grounds for this hypothesis, besides observations on the nebulae. Overlook- ing the zodiacal light, which has been thought a residuum of the nebulous fluid of our system, we find geology taking us back towards a state of our globe which cannot other- wise be explained. It was clearly at one time in a state of igneous fluidity, — the state in which its oblately sphe- roidal form was assumed under the law of centrifugal force. Since then it has cooled, at least in the exterior crust. We thus have it passing through a chemical pro- cess attended by diminishing heat. Whence the heat at first, if not from the causes indicated in the nebular
* Dr. Plateau on the Phenomena presented by a free Liquid Mass withdrawn from the action of gravity. Taylor's Scientific Memoirs. November, 1844.
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hypothesis ? But this is not all. In looking back along the steps of such a process, we have no limit imposed. There is nothing to call for our stopping till we reach one of those extreme temperatures which would vaporize the solid materials ; and this gives us exactly that condition of tilings which is implied by the nebular cosmogony.
Of particular objections it is not necessary to say much. That there should be difficulties attending such a hypothe- sis is only to be expected ; but where general evidence is so strong, we should certainly be scrupulous about allow- ing them too much weight. It is represented, for instance, that the matter of the solar system could not, in any con- ceivable gaseous form, fill the space comprehended by the orbit of Uranus. If this be the case, let it be allowed as a difficulty. It is pointed out that the planets do not increase regularly in density from the outermost to the innermost. Their sizes are also not in a regular pro- gression, though the largest, generally speaking, are towards the exterior of the system. It was not, perhaps, to be expected, that such gradations should be observed ; but, grant there was some reason to look for them, their absence constitutes only another and a slight difficulty. Then we know no law to determine the particular " stages at which rings are formed and detached." Be it so — although something of the kind there doubtless is, as the distances of the planets, according to Bode's law, observe a geometrical series of which the ratio of increase is 2. From these objections, which cannot now be answered, let us pass to some which can.
It has been said that a confluence of atoms towards a central point, as presumed by the nebular hypothesis,
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would result, not in a rotation, but in a state of rest.* According to the North British Review — " . . . Supposing the uniformly distributed atoms to agglomerate round their ringleader, the space left blank by the slow advance of the atoms in radial lines converging to the nucleus, must be a ring bounded by concentric circles, the outermost circle being the limit of the nebulous matter not drawn to the centre of the nascent sun. Now, as all the forces which act upon the agglomerating particles, whether they pro- ceed from the circumference of the undisturbed nebulous matter, or from the gradually increasing nucleus, must have their resultants in the radial lines above mentioned, — there can be no cause whatever capable of giving a rotatory motion to the mass. It must remain at rest."
Now, there can be no doubt that a confluence proceed- ing precisely to a centre, has this result ; but this is only an abstract truth, not an exact and absolute description of any actual confluence of the kind. The explanation was afforded by Professor Nichol, long before the objection was started, and it could not be given in better language on the present occasion : " When we reflect on the solar nebula in the act of condensing, it appears that the act consists in a flow or rush of the nebulous matter from all sides towards a central region ; which is virtually equivalent, in a mechanical point of view, to what we witness so frequently, both on a small and large scale — the meeting and inter- mingling of opposite gentle currents of water= Now, what do we find on occasion of such a meeting ? HerschePs keen glance lighted at once on this simple phenomenon, and drew from it the secret of one of the most fertile pro-
* North British Review, No. 6. Atlas Newspaper, Aug. 30, 1845.
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cesses of Nature ! In almost no case do streams meet and intermingle, icithout occasioning, where they intermingle, a dimple or whirlpool ; and, in fact, it is barely possible that such a jlow of matter from opposite sides could be so nicely balanced in any case, that the opposite momenta or floods would neutralize each other, and produce a condition of cen- tral rest. In this circumstance, then — in the whirlpool to he expected where the nebulous floods meet — is the obscure and simple germ of rotatory movement. The very act of the condensation of the gaseous matter as it flows towards a central district, almost necessitates the commencement of a process, which, though slow and vague at first, has, it will be found, the inherent power of reaching a perfect and definite condition . . ."*
The exception presented by the satellites of Uranus to the otherwise uniform orbitual movements of the planetary bodies, is brought forward as a startling difficulty. f It is, in reality, only a trifling objection, seeing that so many other movements follow one rule, and that we may any day be able to fix upon a cause for this exception, per- fectly in harmony with all the associated facts. There was once a similar difficulty in geology — strata uppermost where they ought to have been lowermost ; but it was in time cleared. Geologists found that there had been a fold- ing over of the strata, so as to reverse their proper and original positions. May we not rest in hope, that a similar exception in astronomy may find a similar solution? I have thrown out the hint of a possible bouleversement of the whole of that planet's system : it has been scoffed at ; but it is only the supposition of a greater degree of obliquity in
* Views of the Architecture of the Heavens. First edition, 1837. t Edinburgh Review, No. 165, p. 24.
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the inclination ot the axis of the planet to the plane of its orbit than what we find in several others. The same causes which made the inclination of the axis of Venus towards her orbit 75 degrees, may have turned that of Uranus a little further along, and so reversed the position of his poles. The admitted inclination of the axis of Uranus towards the plane of his orbit is 79 degrees, the greatest found in any of the planets. This implies only the necessity for an increase of inclination to the extent of 22 degrees, or about one-fourth of the quadrant, in order to account for the surmised reverse arrangement. Nor are causes for such a phenomenon far to seek. In the revolution of the presumed nebular mass, there would be great undulations, as I venture to say there would be found in any similar body which we might set into a similar rotatory motion. Such I esteem as the causes of the departure of the planetary axes from the vertical. A curve in the outermost portion, amounting to a fold — like the curl of a high wave — would cause the bouleversement of Uranus, and the consequent (apparent) retrogression of his satellites.
It appears then, that, overlooking a few minor unex- plained difficulties, the objections to the nebular hypothesis are not formidable to it. It approaches the region of ascer- tained truths, and may reasonably be held as a strong cor- roboration of what first appears from the material laws of the universe, that the whole Uranographical arrangements were effected in the manner of natural law. It is, how- ever, altogether a mistake to regard this conclusion, as far as it is one, as equivalent to a superseding of Deity in the history of creation. It proposes nothing beyond a view of the mode in which the Divine Will has been pleased to
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act, in this first and most important of its works. The formation of worlds and their arrangement now appear but as steps in a Historical Progress, for matter is necessarily presumed to have existed before in a different form. By what means and under what circumstances creation, in the true sense of the word, took place, — that is, how existence was given to the matter which we suppose to have been capable of such evolutions — no one can as yet tell ; we only are sure, if any trust can be placed in the laws of our minds, that it had a Cause, or an Author. Leaving such an inquiry as one, in which we have not, at present, ground for a single step, it is surely a great gratification that we can at least trace the operations of the Great First Cause, from a condition of matter anterior to its present forms, and learn with certainty that these operations were in no way arbitrary or capricious, that they were not single and de- tached phenomena, but the result of principles flowing from the Eternal and Immutable, and which prevailed over all the realms of Infinity at once.
We have fixed mechanical laws at one end of the sys- tem of nature. If we turn to the mind and morals of man, we find that we have equally fixed laws at the other. The human being, a mystery considered as an individual, becomes a simple natural phenomenon when taken in the mass, for a regularity is observed in every peculiarity of our constitution and every form of thought and deed of which we are capable, when we only extend our view over a sufficiently wide range. It is to M. Quetelet, of Brussels, that we are indebted for the first satisfactory ex- plication of this great truth : it is presented in his well- known and very able treatise, Sur L' Homme, et le Dive-
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EXPLANATIONS.
loppement de ses Facultes. He first shows the regularity which presides over the births and deaths of a community, liable to be affected in some degree by accidental circum- stances, but fixed again when these are uniform. He then makes it clear that the stature, weight, strength, and other physical peculiarities of men are likewise regulated by fixed principles of nature. Afterwards, the moral quali- ties,— the impulses of all our various sentiments and pas- sions,— even the tendency to yield to those temptations which give birth to crime, — are proved to be of no less determinate character, however impossible it may be to predict the conduct of any single person. These are doc- trines not to be resisted by inconsiderate prejudices. They rest on the most powerful of all evidence, that of numbers. If they appear to take from the personal responsibility of individuals, it is merely an appearance, for the doctrine immediately steps forward to show that laws, education, and moral influences of every kind exercise an equally determinate control over men ; so that the need for their being called into use becomes even more palpable than before. We are not, however, required at this moment to argue respecting the bearing which this doctrine may have upon human interests. What we are at present concerned with is the simple fact, that Morals — that part of the sys- tem of things which seemed least under natural regulation or law — is as thoroughly ascertained to be wholly so, as the arrangements of the heavenly bodies.
Now we have here two most remarkable truths. The wondrous masses which people the Mighty Void are under the control of natural law. The workings of the little world of the human mind — the opposite extreme of the system — are under law likewise. We have thus the cha-
NEBULAR HYPOTHESIS.
1!)
racter of the limits of the system fixed. So far we proceed upon solid ground. Now it has been seen that phenomena precisely the same as the formation and arrangement of worlds take place daily before our eyes, under the influ- ence of the laws of matter, showing that the whole cosmo- gony might have been effected — proving, indeed, that it was effected — by the Divine will acting in that manner. Having attained this point, we are called upon to remem- ber the many appearances of unity in nature ; how, when we take a sufficiently wide view, there is nothing discre- pant and exceptive in it ; how a noble and affecting sim- plicity breathes from it in every part. So reflecting, we ask, " Can it be that, as the first and the last parts of the system are under law, and the first (this being also the greatest) was manifestly created in that manner, so the whole is under law, and has been produced in that man- ner V It is at the moment when we have arrived at this question, that the origin of the organic world becomes a point of importance. The sceptic of science steps in, and says, " No ; the idea of an entire system under law, and produced by it, here breaks down, for who can pretend to penetrate the mysteries of vitality and organization ? and who can sav that species have had other than a miraculous origin V The tone in which this objection is usually made seems to me inappropriate, considering that the ob- jectors stand on a mere fragment of nature, and one which the discoveries of science are every day lessening. It is but in a nook, to which light has not yet penetrated, that the opponents of the theory of universal order take refuge. On coming to the consideration of the question, I am at the very first struck by the great a priori unlikelihood that there can have been two modes of Divine working in the
20
EXPLANATIONS.
history of nature— namely, a system of fixed order or law in the formation of globes, and a system in any degree dif- ferent in the peopling of these globes with plants and animals. Laws govern both : we are left no room to doubt that laws were the immediate means of making the first ; is it to be readily admitted that laws did not preside at the creation of the second also, particularly when we find that laws equally at this moment govern and sustain both ? Most undoubtedly, it would require very powerful evidence to justify such an admission. And, on the other hand, it would require very decisive counter-evidence to forbid the conclusion that the organic creation originated in law. How actually stands the evidence on either side ? Simply thus : that no actual evidence has ever yet been offered to prove that the Divine will acted otherwise than in the usual natural order in the organic creation ; while, on the other hand, geology and physiology exhibit lively vestiges or traces of that mode having actually been followed. On this narrow ground, it appears, is the great question to be de- bated. If the opponents of the hypothesis of an organic creation by law can bring, from these or any other sciences., facts which appear as powerful objections to any such con- clusion, then it must, at the very least, be held in suspense. If, again, the other party can show these sciences as pre- senting far more argument for a law creation of organisms than against it, the hypothesis must be admitted to have the advantage. I have so presented these sciences ; the evidence has been disputed, and some obscure points have been largely insisted upon in objection. It is now my duty to enter into the consideration of these objections, and see if they are really of the importance which has been attri- buted to them.
GEOLOGY.
21
Fifty years ago, science possessed no facts regarding the origin of organic creatures upon earth ; as far as know- ledge acquired through the ordinary means was concerned, all was a blank antecedent to the first chapters of what we usually call ancient history. Within that time, by re- searches in the crust of the earth, we have obtained a bold outline of the history of the globe, during what appears to have been a vast chronology intervening between its form- ation and the appearance of the human race upon its sur- face. It is shown, on powerful evidence, that, during this time, strata of various thickness were deposited in seas, each in succession being composed of matters worn away from the previous rocks ; volcanic agency broke up the strata, and projected chains of mountains ; sea and land repeatedly changed conditions ; in short, the whole of the arrangements which we see prevailing in the earth/s crust took place, and that most undoubtedly under the influ- ence of natural laws which we yet see continually operat- ing. The remains and traces of plants and animals found in the succession of strata, show that, while these opera- tions were going on, the earth gradually became the thea- tre of organic being, simple forms appearing first, and more complicated afterwards. A time when there was no life is first seen. We then see life begin, and go on; but whole ages elapsed before man came to crown the work of nature. This is a wonderful revelation to have come upon the men of our time, and one which the philosophers of the days of Newton could never have expected to be vouchsafed. The great fact established by it is, that the organic creation, as we now see it, was not placed upon the earth at once ; — it observed a progress. Now we can imagine the Deity calling a young plant or animal into ex-
22
EXPLANATIONS.
islence instantaneously ; but we see that he does not Usu- ally do so. The young plant and also the young animal go through a series of conditions, advancing them from a mere germ to the fully developed repetition of the respec- tive parental forms. So, also, we can imagine Divine power evoking a whole creation into being by one word ; but we find that such had not been his mode of working in that instance, for geology fully proves that organic cre- ation passed through a series of stages before the highest vegetable and animal forms appeared. Here we have the first hint of organic creation having arisen in the manner of natural order. The analogy does not prove identity of causes, but it surely points very broadly to natural order or law having been the mode of procedure in both instan- ces.
But the question is, Does geology really show such a progress of being ? This has been denied in some quar- ters, and particularly in the elaborate criticism upon the Vestiges, which appeared in the Edinburgh Review* In reality, the whole of the geologists admit that we have first the remains of invertebrated animals ; then with these, fish, being the lowest of the vertebrated ; next, reptiles and birds, which occupy higher grades ; and, finally, along with the rest, mammifers, the highest of all ; and yet con- troversialists will be found gravely telling their readers, " It is not true that only the lowest forms of animal life are found in the lowest fossil bands, and that the more com- plicated structures are gradually developed among the higher bands, in what we might call a natural ascending scale the pretext for giving this unqualified contradic
* July, 1845.
t " Edinburgh Review."
LOWER SILURIAN FOSSILS.
'J 3
tion to the above grand fact being, that when we take the special groups of animals, as the invertebrata, the fishes, the reptiles, &c, there are some real or apparent grounds for denying that the low forms of these groups came before the higher. The fallacy consists in sinking the great broad palpable facts of the case, about which not the least doubt anywhere exists, and giving prominence to certain facts of far inferior magnitude, and comparatively obscure, but in whose obscurity there is a possibility of creating a kind of diversion. I trust to be able to show that, even in the special groups of fossils, there is no real obstacle to the theory of a gradual natural development of life upon our planet.
The view which the Edinburgh critic gives of the ear- liest stratified rocks is much the same as my own account of them. There is a Hypozoic formation, or scries, devoid of remains of plants and animals ; then a formation {Lower Silurian) called in my early editions, The Clay-slate and Grawacke system, in which we find " no animals of the higher classes, with a regular skeleton and a backbone only corals, encrinil.es, crustaceans, and mollusks. "Ve- getable appearances," he says, " do not appear among the British rocks ; but there must have been a mass of vegeta- ble life in the ancient sea, as no fauna can appear without a. flora to uphold it." This last inference is of little imme- diate consequence ; but I may remark, that it coincides with one which I ventured to make, prompted thereto by some of the recent papers of Mr. Murchison. We here see it sanctioned by a writer who is understood to be a distinguished investigator of the lowest fossiliferous beds. It is from no wish to amuse the reader, but merely as a pleading in behalf of several of the alleged geological mis
24
EXPLANATIONS.
statements in my book, that I bring forward another dis- tinguished reviewer of the Vestiges of Creation, (North British Review, No. 6), taxing me with having been driven to make this very surmise as an escape from a difficulty ! More than this : the North British Reviewer is at odds with his Edinburgh brother, in bringing bones and teeth of fish into the first fossiliferous formation ; grounding the statement upon Sir Henry de la Beche's Manual, pub- lished about eleven years ago, and contrasting with it, in a foot-note, my remark, " Neither fishes nor any higher ver- tebrata as yet roamed through the marine wilds." The fact is, that this last critic — understood to be a very eminent philosophical writer — was not aware, that since the publi- cation of De la Beche's Manual, the lower fossiliferous rocks had been divided into several distinct formations, in the lowest of which, it is fully admitted, there are no vertebrata. More than this still : a body called the Literary and Philo- sophical Society of Liverpool had brought before them (January, 1845) a set of letters which one of their mem- bers had drawn, with reference to my book, from several of the chief geologists of the day. We there find Mr. Lyell stating upon hearsay, that I represented fish begin- ning in the coal, and Mr. Murchison speaking of me as beginning with zoophytes and polypiaria alone ; statements, I need hardly say, conveying the most erroneous impres- sions regarding the book. This, however, is not the im- mediate point. The two gentlemen here named will be allowed to stand in the very first rank as geologists. They are able men, of marvellous industry, and unimpeached zeal for science. These men, nevertheless, in the corres- pondence to which I am pointing, give entirely opposite views of the first fossiliferous formation. Mr. Murchison
LOWER SILURIAN FOSSILS.
25
says, " No trace of a vertebrated animal has been found in the lower Silurian rocks." Mr. Lyell says, " The fact that, with the earliest type of organization, we meet with vertebrated animals, true fish, so far from being explained away since I affirmed it in my book, is confirmed and ex- tended by fresh evidence." The very latest affirmation we have on this point from Mr. Murchison — an affirmation made after examining Silurian rocks in Russia, where they are presented in vast extent — contains these words : " The absence of even the lowest of the vertcbrata in the inferior Silurian rocks, — an absence which is total, so far as can be inferred from the researches of geologists in all parts of the world, — gives them a true Protozoic character."* These extracts speak for themselves. The only thing calling for further remark, is the surprising circumstance of this correspondence having been brought before a learned society, as wholly and nothing else but a condemnation of the Vestiges !\
A leading objection, with regard to the first fossiliferous formation (Lower Silurian) is, that it does not solely pre- sent animals of the lowest sub-kingdom, as corals and encrinites, but also examples of the two next higher sub- kingdoms, the articulata and mollusca, some of the latter being of the highest order, the cephalopods. The latter particular is what is chiefly insisted upon.
At the time when I wrote, it was understood that the highest orders of mollusca were not found in the first fos-
* Abstract of a paper by Mr. Murchison, Report of British As- sociation of 1844, page 54.
t See Examination of the theory contained in Vestiges of the Natural History of Creation. By the Rev. A. Hume. Liverpool, Whitby, 1845.
8
26
EXPLANATIONS.
siliferous tocks. Professor Phillips, in 1839 (Treatise an Geology), said, expressly, with regard to what was then called the Clay-slate and Grawacke system, " No gastero- pods or cephalopods are as yet mentioned in these rocks in Britain ; and we do not feel sufficiently acquainted with the geological age of the limestones of the Hartz, to intro- duce any of the fossils of that argillaceous range of mountains." So much as a justification of the view given of the Clay-slate fossils in my first edition. Since then, this formation, as it exists in England, has been found to contain gasteropods and cephalopods, though not of such high forms as afterwards appeared. I might here repeat what was remarked in the later editions of the Vestiges, " Even though the cephalopoda could be shown as per- vading all the lowest fossiliferous strata, what more would the fact denote than that, in the first seas capable of con- taining any kind of animal life, the creative energy ad- vanced it, in the space of one formation (no one can tell how long a time this might be), to the highest forms possi- ble in that element, excepting such as were of vertebrate structure." I might add, that this was no great advance in comparison with the whole line of the animal kingdom, if we may take, as a criterion on this point, the analogous progress of an embryo of the highest animals, as the por- tion of that progress representing the organization of the intervebrated animals is only the first month. I might here also revert to the book for some views with respect to the space required for such a development. According to the plan of animated nature, to which I have made approaches in the later editions, we have not to account for the deve- lopment of one long line, but of many comparatively short ones. And, as I have also remarked, there is a rapidity
LOWER SILURIAN FOSSILS.
27
of generation amongst the lower animals which may well suggest something like that " rush of life," which, if we were to judge from British strata alone, would seem to have taken place in the early seas. But, fortunately, none of these speculative answers to the objection are required ; for the question first arises, Does the lowest band of the English Lower Silurians indicate, beyond all question, the point of time at which animal life commenced upon our planet ? Are we quite sure that cephalopoda were among the first of all earth's living creatures? Far from it. It has only been ascertained that certain comparatively small cephalopods are found as far down as any other animals of inferior organization at certain spots in Wales and Cumberland. When we remember that, in modern seas, certain kinds of such animals haunt special places suita- ble for their subsistence — that we may have Crustacea and mollusks exclusively at one place, and radiata (as corals and zoophytes) at some other, not perhaps far distant, but different with respect to depth or some other circumstance — we can conceive that cephalopods may occur in the first fossil bands in the places which have been examined in England, and yet remains of inferior animals may be found by themselves on the same or a lower level in some as yet unexplored place not far off ; so that a time-interval may there appear to allow for a progressive development. Such seems but a reasonably cautious surmise, when we are told by a high authority, that there are " detached Silurian districts in England, presenting particular changes and modifications, arising from difference of depth, and the variety of currents, and chemical combinations in the seas in which they were formed j" and that, " in conse- quence of this variety of physical condition, there is a cor-
IS
EXPLANATIONS.
responding diversity in the traces of organic life in each situation."* What, however, places the matter beyond doubt is, that in North America, where the early stratified rocks are even more amply developed than with us, the highest invertebrated forms do not appear at the first. In the earliest ascertained fossiliferous strata, the Potsdam Sandstone, the only fossils are lingula (a brachiopodous mollusk) and fucoids. In the next, the Calciferous Sand- rock, are fucoidal layers, encrinital beds, and the brachio- pods, orthis, lingula, and bellerophon, together with ortho- cerata, these being the first examples of the cephalopoda. And in all these cases, the fossils are few and obscure ; they comprise no Crustacea. It is not till we ascend to a fourth fossiliferous series, Trenton Limestone, that fossils become abundant, or that trilobites appear. Perhaps even this is not the most decisively adverse view which could be derived from the American fossils, for lately there have been found, in the Green Mountains of Vermont, strata which, from their metamorphic character, are believed by some native geologists to be inferior and of course anterior to the Silurians, and these contain traces of fucoids and of vermiform bodies called Nereites, the last being an humble form of articulata. If this be true, it would at least add materially to the grounds for hesitation before pronouncing definitely, as the Edinburgh reviewer has done, on the commencement of fossiliferous strata and the nature of the first fossils. Here we must also remember, that in rocks of the elder continent anterior to the Silurians, there are limestones, held by many to be an indication of organic
* Professor Phillips, British Association, 1845. Athenaeum's Report.
LOWER SILURIAN FOSSILS.
29
life at the places where they are found : the chemical ex- periments of Braconnot upon masses of these earlier rocks gave ammoniacal and combustible products, likewise indi- cative of the presence of organic matter : in the same sub-silurian region, " fragments, apparently organic, and resembling cases of infusoria," have been detected,* and in Bohemia actual fossils have been announced. Even dubious traces of life in sub-silurian rocks must be admit- ted to be of importance, when we consider that they have mostly been subjected to such a degree of heat as could not fail to obliterate organic memorials, seeing that it has even changed the texture of the rocks themselves. From what Mr. Lyell saw of the Silurian rocks in America, he finds himself called upon, in the most emphatic manner, to warn geologists against " the hasty assumption, that in any of these sections we have positively arrived at the lowest stratum containing organic remains in the crust of the earth, or have discovered the first living beings which were embed- ded in sediment."
" A geologist," he says, " whose observations had been confined to Switzerland, might imagine that the coal mea- sures were the most ancient of the fossiliferous series. When he extended his investigations to Scotland, he might modify his views so far as to suppose that the Old Red Sandstone marked the beginning of the rocks charged with organic remains. He might, indeed, after a search of many years, admit that here and there some few and faint traces of fossils had been found in still older slates, in Scotland ; but he might naturally conclude, that all pre-existing fossiliferous formations must be very insignifi-
* Ansted's Geology, ii., 60.
30
EXPLANATIONS.
cant, since no pebbles containing organic remains have yet been detected in the conglomerates of the Old Red Sandstone. Great would be the surprise of such a theo- rist, when he learnt that in other parts of Europe, and still more particularly in North America, a great succession of antecedent strata had been discovered, capable, accord- ing to some of the ablest palaeontologists, of constituting no less than three independent groups, each of them as important as the ' Old Red ' or Devonian system, and as distinguishable from each other by their organic remains. Yet it would be consistent with methods of generalizing not uncommon on such subjects, if he still took for granted that in the lowest of these ' Transition' or Silurian rocks, he had at length arrived at the much-wished-for termina- tion of the fossiliferous series, and that nature had begun her work precisely at the point where his retrospect hap- pened then to terminate."*
It is exactly to such theorizers as the Edinburgh re- viewer that his rebuke is applicable. When he asserts the contemporaneousness of the highest mollusks with the origin of organic life, he says — " We are describing phe- nomena that we have seen. We have spent years of active life among these ancient strata — looking for (and we might say longing for) some arrangement of the ancient fossils which might fall in with our preconceived notions of a natural ascending scale. But we looked in vain, and we were weak enough to bow to nature." The weakness consisted in looking only in one little portion of the earth, and believing it to be a criterion for all the rest. This writer seems yet to have to learn that knowledge is to be
* Travels in North America, ii., 131.
LOWER SILURIAN FOSSILS.
31
acquired b)' communication as well as examination. Were a philosopher (supposing there could be such a being) to limit his view of mankind to juvenile schools, he might with equal rationality deny that there is any such thing in the world as infants in arms. " We speak of what we have seen," he might say, " and, finding no specimens of humanity under three feet high, we are weak enough to bow to nature and believe that babes are a mere fancy."
Even taking the English Lower Silurians as he and others would have them taken, it still appears that these rocks denote, generally, a low state of the animal kingdom. It is customary for those who take opposite views, to speak of the creatures of this period as high — " highly-organized Crustacea and mollusca " is the usual phrase. Some, in- cluding the Upper Silurians in their view, tell us that the first formation presents examples of the whole of the great divisions, the fish being held as representing the vertebrata. Of course, this is only done through ignorance, or for the purpose of deceiving. Where particulars are overlooked, it is still customary to speak of the earliest fauna as one of an elevated kind. When rigidly examined, it is not found to be so. In the first place, it contains no fish. There were seas supporting crustacean and molluscan life, but utterly devoid of a class of tenants who seem able to live in every example of that element which supports meaner creatures. This single fact, that only invertebrated ani- mals now lived, is surely, in itself, a strong proof that, in the course of nature, time was necessary for the creation of the superior creatures. And, if so, it undoubtedly is a powerful evidence of such a theory of development as that which I have presented. If not so, let me hear any equally plausible reason for the great and amazing fact that seas
32
EXPLANATIONS.
were for numberless ages destitute of fish. I fix my op- ponents down to the consideration of this fact, so that no diversion respecting high mollusks shall avail them. But this is not all. The Silurian is an age, as were several subsequent ones, of only marine animals. It is now in- contestable, from a few land-plants found in the Silurians of America, and a fern leaf in our own, that there was dry land : yet no trace of a land animal appears for ages after- wards. Moreover, though we have now a pretty full de- velopment of the first sub-kingdom, Radiata, we have but an imperfect one of the two next — namely, the Articulata and Mollusca. Not to speak of the utter absence of fresh- water and land mollusks, and of such land articulata as in- sects and spiders, we do not find any decapedous Crustacea (crabs, &c), though these could have lived wherever other mollusks and Crustacea could. In fact, it is a scanty and most defective development of life ; so much so, that Mr. Lyell calls it, par excellence, the Age of Brachiopods, with reference to the by no means exalted bivalve shell-fish which forms its predominant class. Such being the actual state of the case, I must persist in describing even the fauna of this age, which we now know was not the first, as, generally speaking, such an humble exhibition of the animal kingdom as we might expect, upon the development theory, to find at an early stage of the history of organ- ization.*
* Objectors to the development theory have, in the eagerness of counter-theorizing, committed themselves on the subject of the Silurian fossils, in a way which they will yet feel to be extremely awkward. The North British Review we have seen placing even fishes in the first fossiliferous rocks, grounding this statement upon an authority which has been antiquated for fully eight years — avast
UPPER SILURIAN FOSSILS.
33
We now come to the Ujrper Silurians, where new spe- cies of invertebrated animals appear, besides a few obscure fishes. There is no appearance, according to the Edin- burgh reviewer, of a transition from the former species to the present — but does he know the signs by which such a transition could be detected ? I am aware of none. He says the new species are sharply defined — that is, strongly distinct ; and so they may be, without any prejudice to the transmutation theory — as far, at least, as I understand it. And here he remarks that there are the same difficulties in the way of this theory, " both in the grouping of each separate system, and in the passage from one system to another ; and that is true, whatever part of the ascending geological series we choose to take between the lowest formations and the highest." As he does not state the nature of the difficulties, I cannot undertake to say what
period in the history of geology. The British Quarterly Review is equally unfortunate. " The Author's theory," says this writer, " requires that these animals should be the lowest in the scale. But no argument can convert a fish, with its back-bone, and highly- developed nervous and muscular systems, into an animal of low organization." (!) The dogmatic allegations of the Edinburgh re- viewer on this point are sufficiently exposed in the text. I have only further to express my surprise at finding Dr. Whewell par- ticipating in the mere ignorance of the first two of the above-men- tioned journals. In the preface to a volume which he has recently published, under the title of Indications of the Creator, he meets my arguments with a crude and incorrect view of the fossil history, commencing with this sentence — "Vertebrate animals do exist in the Silurian rocks, from which the asserted law [that of develop- ment] excludes them." The existence of a non-pisciferous form- ation had been unknown to him. Many of the objections made to the development theory, in obscurer quarters, rest on errors of a similar kind.
3*
34
EXPLANATIONS.
argument or what reconstruction of my system may be necessary to meet them. Till we are more clear, how- ever, regarding the actual affinities of animals, I would suppose that any judgment as to difficulties in their group- ing in geological formations, or succession in different formations, might well be given somewhat less dogma- tically than they are by this writer.
The few fish-remains of the Upper Silurians may be asssociated with the ample development of this class in the next (Devonian or Old Red Sandstone) system. They belong to Agassiz's two orders of placoids (these by them- selves in the Upper Silurians) and ganoids, the former of which are represented by our sharks and rays, the latter by the bony pike of America and the polypterus of the Nile. Such are the only fishes found till we come up to the chalk formation, when the now predominant orders of cycloids and ctenoids begin.* The Edinburgh reviewer makes a strong point of the placoid and ganoid orders, as unfavorable to the progressive theory. " Taking into ac-
*The North British Review presents, as a strong objection that, " several new ctenoids, which had been found only in the carboni- ferous system, have been discovered among the fishes brought by Mr. Murchison from the Old Red Sandstone of Russia. Resolved to make out his position, the author asserts," &c. This is an un- lucky venture in opposition. The critic evidently meant it to have a very damaging effect, in consideration that the ctenoids are osseous fishes. The fact is, that the fishes brought home by Mr. Murchison are not of the ctenoid order, but belong to a placoidan family called Ctenodus. The mistakes made by this writer, in the geological part of his paper, are of a very grave kind, yet only such as many men of scientific eminence may be expected to make when they venture out of their own peculiar department, and rashly under- estimate the strength of the arguments to which they are opposed.
FOSSILS OF OLD RED SANDSTONE.
35
count," he says, " the brain, and the whole nervous, cir- culating, and generative system, the placoids stand at the highest point of a natural ascending scale, and the ganoids are also very highly organized." Of certain families of the first order, found in the Old Red Sandstone of Russia, he says, " Let the reader bear in mind that these fishes are among the very highest types of their class, and that we can reason upon them with cei'tainty, because some of them belong to families now living in our seas." He in- stances a crestaceon — a high kind of placoid — recently found in the Wenlock limestone, a low portion of the Upper Silurians, and therefore near the beginning of fish. Some of the ganoids, also, of the Old Red Sandstone make an approach to a higher class — reptilia. Besides the usual row of fish-teeth, they have an inner range, in which we see the form of those organs among the sauria. It appears, in short, according to this writer, that the farther back we go among the fishes, we find them possessed of the higher characters. Of the real character of all this hardy as- sertion I shall enable the reader to judge. The fishes of this early age, and of all other ages previous to the chalk, are for the most part cartilaginous. The cartilaginous fishes — Chondropterigii of Cuvier — are placed by that naturalist as a second series in his descending scale ; be- ing, however, he says, " in some measure parallel to the first." How far this is different from their being the highest types of the fish class, need not be largely insisted on. Linnaeus, again, was so impressed by the low charac- ters of many of this order, that he actually ranked them with the worms.* Some of the cartilaginous fishes, never-
* Dr. Fletcher places the Chondropterigii lowest in a scale which
36
EXPLANATIONS.
theless, haye certain peculiar features of organization, chiefly connected with reproduction, in which they excel other fish ; but such features are partly partaken of by families in inferior sub-kingdoms, showing that they cannot truly be regarded as marks of grade in their own class. When we look to the great fundamental characters, par- ticularly to the framework for the attachment of the mus- cles, what do we find ? — why, that of these placoids — " the highest types of their class !" — it is barely possible to establish their being vertebrata at all, the back-bone having generally been too slight for preservation, although the vertebral columns of later fossil-fishes are as entire as those of any other animals. In many of them, traces can be observed of the muscles having been attached to the external plates, strikingly indicating their low grade as vertebrate animals. The Edinburgh reviewer's " highest types of their class " are, in reality, a separate series of that class, — generally inferior, taking the leading features of organization of structure as a criterion, — but, when details of organization are regarded, stretching further both downward and upward than the other series ; so that, looking at one extremity, we are as much entitled to call them the lowest, as the reviewer, looking at another ex- tremity, is to call them the highest of iheir class. Of the general inferiority, there can be no room for doubt. Their cartilaginous structure is, in the first place, analogous to the embryotic state of vertebrated animals in general.*
takes as its criterion " an increase in the number and extent of the manifestations of life, or of the relations which an organized being bears to the external world."
* Cartilage, " in many animals, forms the entire structure, and in the early state of the human embryo it does the same."— Carpen- ter's General Physiology, p. 37.
•
FOSSILS OF OLD RED SANDSTONE.
37
The maxillary and intermaxillary bones are in them rudi- mental. Their tails are finned on the under side only, an admitted feature of the salmon in an embryotic stage ; and the mouth is placed on the under side of the head, also a mean and embryotic feature of structure. These charac- ters are essential and important, whatever the Edinburgh reviewer may say to the contrary ; they are the characters, which, above all, 1 am chiefly concerned in looking to, for they are features of embryotic progress, and embryotic progress is the grand key to the theory of development. I therefore throw back to my reviewer the charge that I have " clung to feeble analogies," and " kept out of view the broad and speaking facts of nature."
With regard to the alleged falsity of the crustacean character of some of these fishes, and the discredit of re- peating the blunders and guesses made by the first obser- vers, before any good evidence was before them, I can only say, that at the time when my book was written, geologists and inquirers into fossil ichthyology of the high- est character were writing, publicly and privately, of the cephalaspis and coccosteus, as apparently links between the Crustacea and fish, the vertical mouth of the latter ani- mal being particularly cited, as a feature indicating the intermediate character. In what the reviewer calls " the excellent work of our meritorious self-taught countryman," Mr. Hugh Miller, published in 1841, the apparently crus- tacean character of these fishes is repeatedly referred to.*
* Mr. Miller calls upon his readers to " mark the form of the cephalaspis, or buckler-head, a fish of the formation over that in which the remains of the trilobite most abound. He will find," he says, " the fish and crustacean are wonderfully alike : the fish is more elongated, but both possess the crescent-shaped head, and
38
EXPLANATIONS.
Not having access at the time to the work of Agassi?, I deemed myself safe in trusting to the report of this indus- trious inquirer and ingenious writer, whose volume was then newly published. How recent the contradiction of the once-supposed affinity may be, or what faith to place in it, I know not ; but the reader will probably hold one who only pretends, in this instance, to the character of a general writer, excused, when he shows so distinguished an expositor of physiology as Dr. Carpenter, still more recently countenancing the idea : — " The bodies of fishes," says he, " are usually covered with scales or plates, which have sometimes a bony hardness, and which, in some species of fish that do not now exist alive, appear to have been of the density of enamel. Thus we have a sort of transition to the external skeletons of the invertebrated ani- mals ; and in this class, also, we not infrequently find the internal skeleton so deficient in the stony matter from which bone derives its hardness, that it seems like cartilage or gristle ; and in a few of the lowest species, we do not even find a distinct vertebral column ; so that the change of character from the vertebrated to the invertebrated series is a gradual, and not an abrupt one, and would probably be found still more gradual, if we were acquainted, not only with all the forms of animal life which now exist, but also those which have existed in ages long gone by, and are now extinct."
ooth the angular and apparently jointed body. They illustrate ad- mirably how two distinct orders may meet. They exhibit the joints, if I may so speak, at which the plated fish is linked to the shelled crustacean. Now, the coccosteus is a stage further on ; it is more unequivocally a fish ; it is acephalaspis, with a scale-covered tail attached to the angular body, and the horns of the crescent- nhaped head cutoff." — Old Red Sandstone, p. 54.
FOSSILS OF OLD RED SANDSTONE. 39
The above argument relates to the general fact of the first fishes being placoidean. It is necessary, also, to meet the inquiry why there should be no fossil remains indicat- ing a transition from the lower animals to fish. The re- viewer speaks of a recently discovered cestraceon below any other fish-beds in England. " Such," he exclaims, " are nature's first abortive efforts." " We entreat," he adds, " any good naturalist well to consider such facts as these, and tell us whether they do not utterly demolish every attempt to derive such organic structures from any inferior class of animal life found in the older strata ? " Now, I cannot tell what good naturalists may say in answer to this appeal ; but I feel, for my own part, that • the facts in question — as far as they can be admitted to be so — have no such destructive effect.
In the first place, the cestraceon is only one of those cartilagines, the real character of which had just been ex- plained. It is not the lowest of its order, but neither is it the highest. So far from this being the case, the respira- tion of the whole family (Selacii, Cuv. ; Plagiostomi, Desm.) to which it belongs, and which also includes sharks, is performed in a manner which approximates these fishes to the worms and insects — namely, t! by numerous vesicles called internal gills, the entrance to which is from their gullet, while the exit is in general by corresponding aper- tures on the side of their neck ; " * other fishes having free gills, marking a higher organization. The sub-divided form of the stomach — the absence of that concentration, which is, perhaps, the most emphatic mark of animal ad- vancement— belongs to this family alone amongst fishes,
* Fletcher's Physiology. Part 1 ., p. 20.
40
EXPLANATIONS.
as it does to the lowest families of several of the higher orders of the vertebrata. Thus, the cestraceon is, on many considerations, a low fish, though certainly possessing some traits of superior character, and not the lowest of its order. In the second place, I would protest against any inference unfavorable to the hypothesis of development being drawn from a discovery so new, so isolated, and in a branch of inquiry so extremely unsettled. At no time during the last ten years, have we had, for a twelvemonth at once, stable views respecting the initiation of fishes. Lately — so lately that part of my book was written at the time — the lowest were understood to be some of a minute size, imme- diately over the Aymestry limestone, in the Upper Silu- rians.* Now, we have a cestraceon announced to us at a lower point in that formation. But how far it is likely that our information is to rest at this point the reader may judge, when he hears of M. Agassiz announcing, within the last few months, that, though acquainted with seven- teen hundred species of fossil fishes, he regards the history of the class as so far from complete, that the number of species successively entombed in the crust of the globe might be estimated at thirty thousand, without any chance of approaching the truth ! f If such be the case, we may surely expect to hear of other fishes prior to or contempo- rary with the cestraceon, showing that, humble as that
* " The minute and curious fishes in the uppermost bed of the Ludlow rock, are the earliest precursors of many singular ichthy- olites which succeed in that enormous formation, the Old Red Sandstone." — Murchison's Address to the Geological Society, February, 1842.
t Review of Professor Pictet's Traite Elementaire de Palaeonto- logie, translated in Jameson's Journal from the Bibliotheque Uni- Verselle de Geneve, No. 112, 1845.
FOSSILS OF OLD RED SANDSTONE. 41
inimal was, it is not to be regarded as the initial of its class.* But even although simpler fishes be not found in lower or contemporary strata, this may only be owing, like the non-discovery of vegetation in the early rocks, to the unsuitablcness of these fishes for being preserved. Sup- posing the inferior tribes, petromyzonidae (lampreys) to have been then in existence, we should have no trace of them preserved, because of their osteological structure be- ing slight, and their wanting those teeth and spines which form, after all, the chief memorials of the higher families of their own order.
One word more as to these fishes. The critic says (p. 33), it is shown to demonstration in the Poissons Fossiles of Agassiz, that " the sauroids, in their general osseous structure, and in the development of their nobler organs, run close upon the class of reptiles." There is no doubt that the sauroid fishes partake of reptilian characters, though, perhaps, in a more external and less important way than such writers as the Edinburgh reviewer suppose ; but, be it remembered, the sauroids are not the first fishes. There is not one of them in the Silurian formation, where placoideans appear to begin. Yet I do not, for this reason, suppose that the sauroids arose from placoideans. More probably, they are part of a distinct line of development,
* Such shifts are of frequent occurrence in geology. Insects, formerly found first in the oolitic formation, are now taken back to the carboniferous. Birds are now inferred from foot-tracks in the New Red Sandstone, their first place formerly being in the oolite. We have mammifers in the oolite, which, a few years ago, were be- lieved not to occur before the tertiary. None of these shifts, how- ever, in the least interfere with the general fact of the advance from the lower to the higher classes of animals.
42
EXPLANATIONS.
which had inferior forms in its first stages, also of too slight a structure to be preserved.
Following this reviewer into his discussion of the Car- boniferous System, we find him commencing with a taunt, that there are now traces of land vegetation in earlier formations. This is, in reality, a point of no importance for the development theory. The question is, with what kind of plants did land vegetation begin ? The anxiety of the reviewer to force a verdict in his favor is here strongly shown. " What," he says, " are these first fruits of na- ture's vegetable germs ? Are they rude, ill-fashioned forms ? Far otherwise. We find among them palms and tree-ferns, &c." In this passage, which substantially con- veys the same information as my book, there is an evident design of inducing the belief, that the first land vegetation was of a high character. The rigid truth is, that though this was a "grand" in the sense of a luxuriant vegetation, it was composed, as far as positive evidence goes, almost wholly of plants which stand low in the scale of organiza- tion. The ascertained dicotyledons (plants having double- lobed seeds and an exterior growth) are extremely rare. On this point, I cannot do better than quote the laborious young Professor of King's College — " The plants which have hitherto been described [in the carboniferous form- ation], belong either to the acotyledonous class, as the ferns, or to the monocotyledons, and, on the whole, they constitute the simplest forms of vegetation ; but there have also been met with among coal plants, unquestionable evidences of dicotyledonous structure, and a genus has been formed under the name of Pinites, to include a number of specimens of fossil wood, &c."* To the un-
* Ansted's Geology, 1844.
FOSSILS OF CARBONIFEROUS FORMATION. 43
doubted evidence of Mr. Ansted, may be added that of his more eminent contemporary, Mr. Lyell, whose sense of the botanical character of this age is such that he emphatically calls it the Age of Ferns.* It is evident, then, taking the landscape of this era as the first, that it is of a nature to harmonize with the development the- ory, for its chief forms are humble, and only a few are of higher grade, most of these, too, being of an interme- diate character between the low and the high. I am re- minded, however, in other quarters, of certain experiments of Dr. Lindley, showing that the plants chiefly found in the coal are of the^inds which best resist decomposition in water ; whence it is inferred that many trees of a high class may have existed at that time, but perished in the sea, while weaker vegetation survived. This evidence would be negative at the best ; and it says as much for the non-preservation of mosses and other humble plants as for dicotyledons. It has also been remarked that, considering such facts as the disappearance of equisetum hyemale in water, a plant containing an unusual quantity of silex, " the proportion of fossil plants in each formation must de- pend on other circumstances besides their power of resist- ing decom position. "f " Too much importance has," in the opinion of the author of this observation, " been attached to Dr. Lindley's experiments.'"'
The British Quarterly Review says — " The author ad- mits there were dicotyledons among these plants, and does not see that, however few they may be, it entirely upsets
* Travels in North America, ii., 52.
t Mr. C. J. Bunbury, at the British Association, 1845 ; Athenae- um's Report.
44
EXPLANATIONS.
the theory of progressive advance, especially in the ab- sence of any proof as to whether they were created first or last." This proceeds, as do many similar objections, upon the idea that a formation represents one point in time. A formation, in reality, represents many years, or rather ages. Such expressions as that simple and complex plants occur together in the carboniferous formation, or even (shall we say) in its first fossil bands, are vague ex- pressions, perhaps conveying an idea substantially false. There is no such precision in the ascertained relations of fossils to particular strata, as to entitle any one to say that the simple and complex plants of this vfprmation are rigidly contemporaneous. They may have followed each other within the space of half a century in a particular region, and yet been preserved in but one stratum, or little group of strata. The actual appearances of the carboniferous form- ation thus, perhaps, allow full time for a progressive ad- vance in particular regions, from the fleshy luxuriant plants of the marsh and low sea margin, to the robust tree of the more elevated regions. We must remember, too, that the vegetation of the carbonigenous era, even if we take it back to include the confer said to have lately been found in the Old Red of Cromarty, or the fern leaf of the Silurians, was preceded by unequivocally simple plants in the fucoids. Starting with these, and finding the first great burst of land vegetation composed mainly of low cryptoga- mic and monocotyledonous plants, — finding, moreover, the exceptions chiefly of the intermediate character, and that the dicotyledons increase afterwards while the others de- cline,— we cannot well resist the conclusion, that we see the traces of a progress in the history of this kingdom of nature. It may be less clear than we could wish ; but
FOSSILS OF THE PERMIAN SYSTEM.
45
Buch light as we have certainly favors the development theory.
We now come to the Magnesian Limestone deposit, lat- terly called the Permian System. At this place, the Edin- burgh reviewer introduces some general observations, which I hope he will yet acknowledge to be unjust, as I am sure the whole of his substantive charges are. " It may be true," he says, " that sea- weeds came first, but of this we have no proof." How a. good geologist can have allowed himself to speak in this manner, even in eager- ness to theorise against theory, I am quite at a loss to un- derstand, for the positive facts of the occurrence of fucoids in the Lower Silurians, and of the very first traces of land vegetation in subsequent formations, are as palpable and undoubted as he himself acknowledges the precedence of fish by invertebrata to be ; nor has any one ever pretended to expect that land vegetation would be found earlier than the marine. I have here ventured no conjecture of my own, but only spoken as all the geological books teach. " Of land plants," he continues, " we have not the shadow of proof that the simpler forms came into being before the more complex." The reader has just been told upon un- doubted authority that, in the first great show of land vege- tation, taking such positive evidence as we have, the sim- ple forms are vastly more numerous than the complex. Finding that we have first ample marine vegetation, then a land vegetation in which the plants, with only a small exception, are cellular and cryptogamic, while of the ex- ception a very small number are dicotyledonous, and a con- spicuous group (the conifers) intermediate — I feel that I am entitled to say that positive evidence speaks for a pre- cedence of high but simple forms ; which is what I have
46
EXPLANATIONS.
done. " It is true," thus proceeds the reviewer, " that we see polypiaria, crinoidea, articulata, and mollusca ; but it is not true that we meet with them in the order stated by our author." It is humiliating to have to answer an objec- tion so mean. There is no statement that the animals came in this order. I have only put the words into this arrangement, in accordance with the custom now commonly followed of observing the ascending grades of the animal kingdom. With respect, then, to what follows — " The sentence on which we here comment contains three distinct propositions, and all three are false to nature, and no better than a dream," — I believe I may safely leave the reader to say which party is the falsifier and the dreamer. He goes on in the same strain — " It is true that the next step gives us fishes ; but it is not true that the earliest fishes link on to the radiata : this is a grand and at the present day an unpardonable blunder." This is another dream of the reviewer, for certainly such an affinity was not sug- gested in any edition of the Vestiges hitherto published. In the first four editions, which alone were under his no- tice, no passage except from the articulata was even hinted at. So much as a proof of the reviewer's recklessness in making charges ; there is no need, however, to affirm, with him, that a connexion between certain high radiates and some of the lowest fishes does not exist. I venture to pre- dict that affinities of an equally startling nature will yet be made familiar to naturalists. Meanwhile, it is enough to show that this confident critic has raised an accusation for which he has not a shadow of ground.
Taking up the special fossils of the Permian system, he says, " The earliest reptiles are not of such a structure as to link themselves, on a natural scale, to the noble sauroids
EARLIEST REPTILES.
47
sf the preceding carboniferous epoch." They are not the iiarine saurians, or fish lizards (ichthyosauri) which occur in a higher formation, but lacertilians, or animals of lizard-like character. Now what first strikes me here is the extraordinary narrowness of a mind which sees no- thing indicative of natural procedure, no hint towards great generalizations, in the simple fact of reptiles following upon fish in this grand march of life through the morning time of the world. He knows that, in every classification of the animal kingdom, reptiles rank next above fish, that in some living families there is such a convention and intermixture of both characters, that naturalists cannot agree to which class they should be assigned. He actually sees, in a general view of the earlier reptiliferous forma- tions, animals combining the fish and reptile in the most unequivocal manner. Despising, however, the great fact which shines through these obscurities, this person, and I am sorry to add, geologists generally, can only fasten upon such particulars as may be made out to be difficulties in the way of generalization. Passing to the particulars, a few land lacertilians come first, whereas the first, according to my hypothesis, ought to be marine forms, and linked to fish. He says of this difficulty, that I have stated it feebly. Perhaps it would have been well for his own credit that he had stated it somewhat less confidently ; for before his sheets had seen the light, a prospect had arisen of his affirmations on this point being thoroughly falsified. In SillimarCs Journal, for April, 1845, is an account of sand- stone surfaces pretty far down in the Carboniferous forma- tion of Pennsylvania, marked with the vestiges of terrestrial animals. Setting aside in the meantime one class of these markings, which are said to indicate wading birds, we
48 EXPLANATIONS.
have a variety of others plainly denoting reptiles. In one group, the foot consists of a ball, with five toes radiat- ing from it in front. In another, the impression resembles that made by a coarse human hand, with the rudiment of a sixth toe at the outside. The reptilian families indicated by these foot-marks have not yet been pronounced upon,
as far as I am aware : but from the extreme resemblance
i '
of some of them to the vestiges of the labyrinthidon, there can hardly be a doubt that some of the order batrachia are amongst them. If they prove wholly batrachian, as is not unlikely, for we have living families with feet resembling the first group of vestiges, or even if only a portion of them be certified as of this order, where will be the lacer- tilians, and where the confident counter-assertions of the Edinburgh reviewer ? The batrachia he has himself allowed to be a low order of reptiles (p. 51). They are so considered by all naturalists. Might 1 not here, then, take my stand upon the fact of animals, the lowest apparently of the reptile order, being now found at the earliest point of time ? I might unquestionably do so with a decided immediate advantage to my hypothesis. It would in a great measure neutralise the whole of the objections of the reviewer with regard to the chronology of the reptiles. But I am, whatever he may think of me, willing to read the book of nature aright. I receive the fact as one liable any day to receive a new aspect from fresh discoveries. In as far as it is so, it only teaches that we are not to be too confident in drawing inferences either for or against the theory of development from the particular succession in which the orders of the reptilia occur in those early strata where their remains and vestiges are few. In as far as it may be taken as a positive fact, I only
DEVELOPMENT OF THE ANIMAL KINGDOM.
49
claim a modified benefit from it, because the view which I take of the affinities and connexions of the animal king- dom (and by analogy of the vegetable kingdom also) makes it a matter of less consequence than would be generally supposed, which order of any class appears first in the stone record, though still perhaps a matter of some consequence.
This view suggests that development has not proceeded, as is usually assumed, upon a single line which would require all the orders of animals to be placed one after an- other, but in a plurality of lines in which the orders, and even minuter subdivisions, of each class, are ranged side hy side. It also suggests that the development of these various lines has proceeded independently in various regions of the earth, so as to lead to forms not everywhere so like as to fall within our ideas of specific character, but generally, or in some more vague degree, alike. The progress of the lines becomes clearest when we advance into the ver- tebrate sub-kingdom. We can there trace several of them with tolerable distinctness, as they singly pass through the four classes of Fishes, Reptiles, Birds, and Mammals ; the Birds, however, being a branch in some part derived equally with the reptiles from fishes, and thus leaving some of the mammal order in immediate connexion with the reptiles. The lines or stirpes have all of them pecu- liar characters which persist throughout the various grades of being passed through, one presenting carnivorous, another gentle and innocent animals, and so on. We have, therefore, in the animal kingdom, not one long range of affinities, but a number of short series, in each of which a certain general character is observable, though not always to the exclusion of the organic peculiarities of 4
50
EXPLANATIONS.
families in neighboring lines, especially in the class of reptiles.
According to this view, the matrix of organic life is, speaking generally, the sea. Fluid, required for all embryotic conditions, is also necessary to the origination of the various stirpes of both kingdoms. The whole of the lowest animal sub-kingdom (Radiata) is aquatic : so are nearly the Mollusca and a very large proportion of the Articulata. In the Vertebrata, the lowest class also is wholly aquatic. The arrangement appears to be this — the basis of each line is a series of marine forms ; the remainder consists of a series designed to breathe the atmosphere and live upon land, these being all of improved organization. The classification which this system implies may be said to be transverse to all ordinary classifications. The invertebrate, ichthyic, reptilian, ornithoid, and mam- malian characters are horizontal grades, through which the lines pass, and where they send off branches ; not separate and independent divisions. In any of these branches where we have a clear knowledge of the various forms, it is possible to trace the affinities, in conjunction with an improved organization, through genera which are adapted to a partially marine life, to a residence in the mouths of rivers, or on shores and muddy shallows, then through genera which are, in succession, appropriate to marshes, jungles, dry elevated plains, and mountains. And it is this series of external conditions and adaptations which has caused that system of analogies between various families of animals which has of late attracted attention. But the immediate cause of the development of each line through its various general grades of being is to be sought in an internal impulse, the nature of which is unknown to
DEVELOPMENT OF THE ANIMAL KINGDOM. 51
us, but which resembles the equally mysterious impulse by which an individual embryo is passed through its suc- cession of grades until ushered into mature existence. Geology shows us each line taking a long series of ages to advance from its humble invertebrate effluents to its highest mammalian forms ; and this I have ventured to call " the universal gestation of Nature."
The traces of this order of the animal kingdom have been seen in all ages of science. Every zoologist ac- knowledges the gradations and affinities which appear amongst animals. Prompted by what so palpably meets observation, many have tried to range the various orders or families in one line, or (to use the favorite phrase) chain of being ; but they have always failed, which is not to be wondered at. One cause why zoologists have not up to this time thought of trying any different arrangement, is the confusion arising from prevalence amongst many families of parallelisms of structure, which have been regarded as affinities, when in reality they are only identi- cal characters demanded by common conditions, or result- ing from equality of grade in the scale. True affinities — and these are the affinities of genealogy — are not to be looked for horizontally amongst orders, but vertically, from an order in one class to the corresponding order in the class next higher. Generally, the first and lowest forms of the orders in a class are marine, and often these are of comparatively large size. We usually see in them a vestige of the essential characters of the class next below. Thus, the perennibranchiate batrachia in their order, the ichthyosauri in the series of crocodilia, and the divers among birds, all exhibit an affinity to fish. The cetacea and phocidoe, which I regard as the immediate basis of the
52
EXPLANATIONS.
pachydermata, carnivora, and other orders of terrestrial mammals, ought, according to this view, to show an alliance to the reptiles ; and such a connection does exist between the cetacea and certain marine sauria ; but from the general extinction of the marine reptiles, the linking of the mammals to that lower class is less clearly seen than might be wished. It must be kept in view that only an outline of the progress of the animal kingdom is here designed. Exceptions as to the course which development has taken appear to be by no means few ; leading to the idea that the grades of organization are not determinate in this respect, but may be reached by steps of unequal length. Thus, for example, the marsupials appear very clearly a development from certain birds ; probably the rodent and edentate orders are derived through the same channel. From the approach made by certain of the reptilia to birds, we may surmise that there also there are exceptions to the rule. In short, the progress of animality in the different stirpes has been attended by peculiarities which evidently affix peculiar characters to each, and make the idea of a difference in time not only probable, but unavoidable.
Regarding the animal kingdom simply as a combination of independent stirpes, each with its distinct affinities, the theory of transmutation puts on a totally new aspect ; so truly is this the case, that transmutation is hardly any longer a term appropriate to the idea. The difficulty of supposing such changes as that from the rodent to the ruminant, or the carnivorous animal to the quadrumane, vanishes, leaving only transitions from one form to another of a series generally similar — from the aquatic pachyderm, for instance, to the terrestrial, from the otary to the otter,
EARLY REPTILIAN FOSSILS.
53
from certain phocEe to the bear, and so on. There is a unity in all instances in the moral as well as physical characters of the various members of one stirps ; we only see it advancing from low to high characters, just as we see the foetus of a high animal passing through various inferior stages before it reach its proper mature character. The lines, moreover, being independent of each other, and not quite uniform as to the stages of animality through which they pass, it follows that, unless we knew of some law governing their different gestative periods, we are not entitled to look for the first occurrence of their various ichthyic, reptilian, and mammalian sections, in any order as regards each other, even though we could be sure (which we are not) that we are surveying a geographical region where they all started fair in the race of progres- sive organization. Hence it is that, though the batrachia are usually placed by zoologists at the bottom of the list of reptilian orders, I attach little importance to their ves- tiges being now found so low. All that I think we can expect is, that, in a particular area where we have reason to believe that the lines have started abreast, they should all reach their various grades nearly about one time, or what may be considered as one time compared with the whole extent of geological chronology. And such ap- pears to be pretty much the case in those regions which geologists have explored.
The Edinburgh reviewer will observe that this view of the animal kingdom leaves much of his opposition in a very awkward predicament. He has everywhere assumed that the genealogy of the orders of each class was sup- posed to be en suite, which it certainly never was in my book. In the early editions I spoke with diffidence of the
54 EXPLANATIONS.
course of the supposed development,* because I had not then seen or conceived any arrangement of the animal kingdom which answered to that hypothesis, although I thought proper to attempt to show that the quinarian and circular classification, which I found in vogue at the time when I was writing, did not necessarily militate against it. In the third edition, the present view was first hinted at ; and in the fourth it was sketched, though with liability to correction ; thus anticipating by some months the pub- lication of the criticism to which I am adverting. I need hardly remark, that in all criticism, the actual subject criticized must be brought forward for comment, and nothing else ; otherwise the commentaries become of no imaginable use but to obscure true judgment. Now the Edinburgh reviewer has presented his subject, in this in- stance, in lineaments entirely of his own imagining, and directly in contradiction to those which belong to it. He had no title to assume any plan of development and to represent his victory over that as a triumph over the hy- pothesis of his author. In such conduct, he has thoroughly vitiated the whole fabric of his criticism, and left it, in reality, no pretension to remain for a moment in court. My immediate object, however, is not to take such excep- tions against him, but to show how the ascertained facts of a limited portion of the field of nature may be recon- ciled with that conception to which a view of what ap- pears over the whole field may lead an honest inquirer. If the hypothesis of a plurality of genetic lines be ad-
* " . . it does not appear that this gradation passes along one line, on which every animal form can be, as it were, strung ; there may be branching or double lines at some places," &c. — Vestiges, let ed.,p. 191.
EARLY HCrTlLIAN FOSSILS.
55
mitted, we are not of course to ask which order of rep- tiles, or of any other class, first existed (such being the language of the old classification) ; but, having first set- tled the whole affinities of the animal kingdom on the new plan, we are to inquire if the geological presentment of the families was accordant with the scheme, allowing for the negative nature of much of the geological evidence of this kind. Now, in the first place, the affinities of the animal kingdom are only in part made out ; in the second, geological evidence is only partial. We are clearly, therefore, not to expect in nature's museum a full exhibi- tion of any one entire stirps, as it may be supposed to have passed through its successive stages up to our time. All that we can expect is a succession of fossils marking out portions of what we may suppose likely yet to be es- tablished as lines of animal descent. Blanks, and large ones too, must be allowed for ; possible errors as to the animal pedigrees must be contemplated. But, if we have any ground for generalizing in a particular direction, as I think there is in this case, we may be held as called upon not to conclude hastily and rashly on the unfavorable side, but to look and consider patiently, and to suspend judgment wherever the adverse evidence may appear to be of a nature likely to be reversed. Let us now see how all this applies to the conduct of the Edinburgh re- viewer, with regard to the early reptilian fossils. The formations where these occur have only been examined in such a degree, that they are almost every year giving forth new responses : for example, the existence of birds at this era was not dreamt often years ago ; the existence of tortoises in the time of the New Red Sandstone was equally unknown only two or three years earlier. It is
56
EXPLANATIONS.
a still less time since the labyrinthidonts of the Keuperof Germany were discovered ; and we have just seen that the unqualified affirmations of the Edinburgh reviewer, as to the oldest reptiles, were overturned by intelligence from America, before his sheets had seen the light. When these things are considered, we must see the objections of the reviewer to be extremely rash. It might be allowed that the earliest known lacertilia are not of strictly ma- rine forms or allied to fish ; it might equally be admitted of the first batrachians, that " their near affinities are not with fishes," as this writer takes it upon him to say. Yet we should still see the absurdity of affirming that either these batrachia or lacertilia were the first created of their respective orders, seeing that their relics were so few and the discovery of these so accidental, that we might look for new and superseding facts every day.*
But, as the case actually stands, is this line of defence more than hypothetically necessary ?' I doubt it very much. The lacertilia of the magnesian limestone, and these labyrinthidonts of the Trias (perhaps also of the carboniferous formation), are they so far removed from fish characters as the reviewer would make them ? Let any naturalist who has ever studied the transmutation of
* It is necessary to guard against a supposition that I undervalue such isolated relics, as inferring the positive fact of the existence of particular orders of animals at particular times. For this pur- pose, the smallest fragment betraying the character of the organiza- tion is often sufficient. What is really meant is, that, when we find a few outlying relics belonging to a class which does not ap- pear in any force till afterwards, we cannot be sure that we have acquired the means of forming a distinct idea of the lime of the origin of that class or the orders with which the class started, as further discoveries on these points may be looked for.
EARLY REPTILIAN FOSSILS.
57
the individual batrachian, passing in a few weeks from the branchiated fish to the lunged and limbed frog or newt, its circulatory and alimentary system entirely changed, and then say if the labyrinthidon may not be the very first step from some ichthyic form. What though the propor- tions of the head remind Mr. Owen of the sauria, and re- move the animal, as he thinks, above the present batra- chian type ! Against any such inferences we have the positive fact, in the organization of this batrachian, of a biconcave form of the vertebrae, the form peculiar 1o fishes, — arguing, by Mr. Owen's own acknowledgement, aqua- tic if not marine habits, — also a decidedly piscine charac- ter in the arrangement and even microscopic structure of the teeth, together with that position of the breathing apertures near the end of the snout which we see in croco- diles, for the purpose of allowing them to drag their prey under water without ceasing to respire. With regard to the lacertilia, we have this same fish-like biconcave form of the vertebras, and the same fish-like arrangement of the teeth, equally arguing that alliance to the lower vertebrate class which it is the pleasure of this hardy critic to deny, — the biconcave structure of the reptiles, showing, as Mr. Owen himself owns, that these animals, which the Edin- burgh reviewer deems so utterly separated from fish, had probably " a more aquatic, if not marine theatre of life,'"* than was assigned to their successors. In subsequent and present reptiles, this form is superseded by the ball and socket, or concavo-convex form ; but it is remarkable that, in the embryo state, the frog and crocodile (if not
* On the Reptilian Fossils of South Africa. Geological Trans- actions, Feb., 1845.
4*
58
EXPLANATIONS.
others) exhibit the double hollow form still, resembling in this respect the mature animal of the secondary rocks. Such is the actual character of reptiles which our critic would set up as high : he has, after this, only to speak of the annelid as above the butterfly, or the proteus as su- perior to the land salamander, to establish his character as a naturalist. Need I say that these Permian reptiles are, in reality, by these facts degraded to a place in prox- imity with fishes ?
So much for the batrachia and lacertilia. When we come to the great saurian line in the Muschelkalk, Lias, Oolite, and Wealden, we have a case which cannot be disputed, for here the marine character of the earliest of the series, and their intermediateness between fish and true crocodiles, are admitted by all. The first remove from the fish is the ichthyosaur, its name declaring the convention of class characters for which it is remarkable. With piscine body and tail, and fins advanced into a paddle form, it has a true crocodilian head. In the pliosaur, which is later in appearing, we have a stage of advance to the true sauria, which come forward in the oolite, in the forms of teleosaurus, steneosaurus, &c. Afterwards, chiefly in the Wealden, we have the dinosauria, which betray an approach to the mammalian type in the pachydermatous order. Another oolite saurian, the cetiosaur, exhibits in the form of the vertebrse a verging towards the cetaceous mammalia. Here there is the most perfect and even striking harmony with the theory of a progressive deve- lopment. Below these formations, fish : then, low in these formations, fish saurians ; above them, true and complete saurians ; finally, higher still, saurians advancing to a more elevated grade of animality ; and where do these
EARLY REPTILIAN FOSSILS.
59
more elevated types occur ? In tiie next formation, pass- ing over one which hardly represents any but deep-sea life. Nay, cetaceous relics have been found before we leave the strata so remarkable for the saurians. Thus, it appears that the whole of this chapter of palaeontology, when read by a light from nature, and not from man's capricious hu- mor, so far from being opposed to the natural genesis of animals, gives it support. Men, however, and of lively parts too, might go on for an age misreading such palpable facts, if they be determined against putting them into the collocation in which a sense can be made of them, just as we might puzzle for ever over a Latin or Greek sentence, if obstinately resolved against making English out of it ex- cept in its original construction.
After presenting the case of the reptilian fossils of the secondary formation in this way, I feel it hardly necessary to track the Edinburgh reviewer through all his particular objections. They are a mass of confusion, resulting from erroneous assumptions on his own part respecting the de- velopment theory, as that the orders of animals are all to be affiliated to each other, and every parental form held as extinguished by the fact of transmutation (the latter being a peculiarly gratuitous supposition — see p. 50 of the Review) ; together with equally rash and unjustified con- clusions regarding the earliest forms of the reptilian orders, all mixed up in the way that promised to tell most effec- tually in favor of his own opinion, and with a disregard of everything that pointed in the opposite direction. The great unquestioned facts of a succession of birds and mam- mals to the fishes and reptiles, these being also the next higher classes in the scale of the naturalist, tell nothing to this writer, as the succession of the reptiles to the fishes
60
EXPLANATIONS.
told nothing before. From the slight remarks with which he passes over these facts, an unlearned reader would hardly suppose that they were of the least significance, while, in reality, they are of the greatest. It is much the same as if a historian were to sink all such events as changes of dynasties, and fix attention upon the displace- ment of under-secretaries of state. And what makes this conduct the more marked is, that the minor facts upon which he fastens for the purpose of supporting his own theory, are mostly presented to us in circumstances which show their uncertainty and the likelihood of their being superseded.
For example, the earliest traces of birds do not indicate marine forms, which, according to my general views, ought, he says, to be the case. Instead of natatorial birds, they are waders and runners. Let the reader judge of the character of this objection, when he learns the real circumstances of the case. The traces of birds here spoken of are merely a few foot-prints found upon certain rock surfaces in America. Not a bone of these animals has been found in this early period. It must therefore be inferred, either that the circumstances were not favorable for the entombment of the bodies of these birds, or that our researches in the strata formed at the time when they lived have been insufficient to discover them. If such be the case with birds which lived upon shores, — places where, as we learn from the nature of the strata, accumulations of sand and mud were constantly taking place, — it is of course -not to be expected that any remains of natatorial birds should be found, animals mostly living far out at sea. To put the case in its strongest form — foot-prints on shores being the record of the birds of this era, we are not
EARLY CETACEOUS FOSSILS.
61
to expect any traces of such birds as, generally speaking, are not in the way of making foot-prints on shores. I might go further than this, and point out that certain nata- torial genera have feet not to be distinguished from those of waders, so that certain of these foot-prints may be those of natatorial species after all ; but I feel it to be my best duty in the case, only to deny that we are in circumstances to say that waders and runners were the first created birds. Mr. Lyell, who stands as high as this or any other writer on geology, says, with regard to those very ornithichnites, as they are called — " This sandstone is of much higher antiquity than any formation in which fossil bones or any other indications of birds have been detected in Europe. Still we have no ground for inferring from such facts, that the feathered tribe made its first appearance in the western hemisphere at this period. It is too common a fallacy to fix the era of the first creation of each tribe of plants or animals, and even of animate beings in general, at the precise point where our -present retrospective knowledge happens to stop."* What now gives force to this observation is, the recent dis- covery of a new set of bird foot-prints — said to be of waders only — in the carboniferous formation of Pennsylvania. The emergence of such a fact in the midst of the review- er's speculations on the foot-prints of the New Red Sand- stone, forms a most emphatic commentary on all decisive inferences where the facts are obviously casual and isolated.
Of a somewhat different character are the reviewer's remarks on the first relics of mammalia — the few bones of cetacea from the Lower Oolite and of marsupials from the
* Travels in North America, i., 255.
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EXPLANATIONS.
Stonesfield Slate. Here the very first mammal family is undoubtedly marine ; and, if it were to receive equal con- sideration with the grallatorial foot-prints, he ought cer- tainly to admit that it favors the development theory. But he escapes from this claim by a mode of his own. He has not seen these relics ! The American foot-prints were good evidence, without being seen ; but a fact which makes against his theory requires personal inspection, even though it may come forward with the authority of Baron Cuvier.* He is more at ease with the marsupials, which are of course unequivocally land animals. I have only here to refer to the fourth edition of my book — published two months before the appearance of the review, and while I was unrecking of any great objection being grounded on this point — where it is suggested that the peculiar organi- zation of the marsupials points to their having been derived through a different medium from other mammals. The critic, eager to let nothing escape, tells us that there are other land mammals lower in organic type than the mar- supials. One answer to this objection might be found in an explanation of my views respecting the ornithic descent of these animals ; but I am unwilling to pause upon such an inferior matter, and will therefore meet him with the question, if any other mammals show that lowly grade of organization which is marked by the absence of a placenta ? " There are no other organic types," he says, " to which they [the marsupials] offer the shadow of a near affinity.
* " There is in the Oxford Museum an ulna from the Great Oolite of Enstone, near Woodstock, Oxton, which was examined by Cuvier and pronounced to be cetaceous ; and also a portion of a very large rib, apparently of a whale, from the same locality."— Buckland's Bridgewater Treatise, i., 115, note.
AFFINITIES OF MARSUFIAL1A.
63
They are therefore in direct antagonism with the scheme of regular development." To this it may be replied, that the affinity of the marsupials to the oviparous vertebrata is admitted by every naturalist, being shown in the small size of the brain and consequent exposure of the cerebellum, the absence of the septum lucidum and corpus callosum in the brain, and various other traits. Professor R'ymer Jones, of King's College, whose testimony on such a point will be admitted by the reviewer, speaks of the marsupials as " connecting links between the oviparous and placental vertebrata." Striking traits of their affinity to birds are shown, he says, in the structure of the ear and of the re- productive organs.* In reality, the whole figure of the cursorial bird, the small head upon the long neck, the ex- treme length of the hinder limbs, and the imperfect deve- lopment of the fore extremities, as well as the tendency of the feathers to a hair-like character, speak irresistibly for its approach to certain marsupials. The ornithorhynchus is as clearly an advance from the natatorial bird towards the rodent form, the latter being an order whose osteologi- cal structure is allowed by every naturalist to be bird-like. New and curious illustrations of the connexion between the birds and the implacental mammalia are constantly ap- pearing. We lately heard of a bird which has a pouch for its young like the kangaroo,! and Mayer has discovered in the female emeu a purse form of certain organs, indi- cating an approach to the marsupial in that part of struc- ture which is the most distinctive in the case.:}: It would appear that the reviewer is simply ignorant of this depart- ment of natural history, and, with the self-esteem which
* General View of the Structure of the Animal Kingdom.
f Magazine of Natural History. J Reports of Ray Society, I.
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EXPLANATIONS.
often attends upon ignorance, he has somewhat unluckily ventured to give a positive contradiction to that which is incontestably true.
The reviewer at length comes to the organic phenomena of the Tertiary system. " On the theory of development," says he, " ' the stages of advance are in all cases very small — from species to species,' and the phenomena, ' as shown in the pages of geology, are always of a simple and modest character.' Let us test these assumptions by one single step, from the chalk to the London clay, or any other tertiary deposit. Among the millions of organic forms, from corals up to mammals, we find hardly so much as one single secondary species." The exceptions in reality are, the infusoria of the chalk, and "two or three secondary species," which are said to " straggle into the tertiary system." " Organic nature," he says, " is once more on a new pattern — plants as well as animals are changed. It might seem as if we had been transported to a new planet ; for neither in the arrangement of the genera and species, nor in their affinities with the types of an older world, is there the shadow of any approach to a regular plan of organic development." Now the almost total break in the organic creation here insisted upon, occurs in the interval between the extensive deposits of the secon- dary formation, and the comparatively isolated deposits of the tertiary. It is an interval which the lithological arrangements clearly indicate to have been longer than any of those between the other formations, during which minor changes of organic creation had taken place. It is simply, then, a period not represented by strata or by fos- sils ; while it elapsed, the continual advance of the organic world proceeded to a point at which nearly all the old spe-
*
TERTIARY FOSSILS.
65
cies had died out or been changed. There was nothing more in the "step" of our reviewer than this. Such is the geological doctrine. " Is the present creation of life," says Professor Phillips, "a continuation of the previous ones ; a term of the same long series of communicated being ? I answer, yes."* " There is no break," he says, " in the vast chain of organic development till we reach the existing order of things." The reader will further be able to judge of the candor of the reviewer respecting the zoology of the tertiary, when he is reminded that it shows exactly those new portions of the animal kingdom which might have been expected, according to the theory of development. Heretofore, we have only few and faint traces of mammalia ; but now they are added in abun- dance, mammalia being the crowning class of the verte- brated form. As far as class, therefore, is concerned, it is incontestably a " regular plan of organic development." But this is not all. We have seen the reptile forms of the secondary approaching the cetacean character ; and now there is an abundance of the aquatic mammalia, as well as of those land pachyderms which are universally classed with some of the forms of that order, these being the only suite of creatures which my ideas of development would lead me to expect at this place. Here I must meet the reviewer on a special ground. He admits the dinosaurs to have been the nearest approach to mammals ; but " they died away," he says (" if we are to trust to geology), ages before the end of the chalk." These mammals have, therefore, " no zoological base to rest upon." That is, there is no connection between them and any such animals
* He adds — " But not as the offspring is a continuation (f the parent."
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EXPLANATIONS.
as the dinosaurs, because there is an interval in the creta ceous formation which gives neither these forms nor any intermediate. Now, the fact is admitted by Professor An- sted, that the cretaceous system appears to have been " formed, for the most part, by deposits in deep water, and a considerable portion of it not far from the zero of animal life"* And this he states with a particular reference to the results of Professor Edward Forbes's researches in the Egean sea. We therefore have a satisfactory explanation of the non-appearance of forms intermediate to the rep- tiles and mammals in the chalk, without being driven to suppose, with our reviewer, that the latter were a creation de novo of animal life. But no such fact as this did it suit our reviewer to state.
" Carnivora," he proceeds to say, " are as old as pachy- derms. As far, at least, as we have any evidence bearing on the question, and bimana (monkeys) are found in this division — thus contradicting and stultifying the upper end of our author's grand creative scale." There is here, in reality, no stultification except in the critic's own mind. It was not my scale which he refers to, but Dr. Fletch- er's ; adopted into my book, not as a plan of the actual process of development, but as a general indication of the comparative organization of the animal orders. I do not consider the assumed contemporaneousness of the carnivora and monkeys (which the reviewer erroneously calls bima- na) as at all contradictory of a true development theory, for I regard them all as distinct lines of development, which might well advance to a certain stage (namely, that of the terrestrial mammal), about the same time. I am
* Ansted's Geology, i., 502.
TERTIARY FOSSILS.
07
not, however, entitled to blame the reviewer for this objec- tion, as the idea of a development in a plurality of lines must be new to him.
" As we ascend," he says, " towards the middle divi- sions of the [tertiary] series, there is a development of nature's kingdom, nearer and nearer to living types. But it is not a development after our author's scheme. It fol- lows the law of the rise, progress, and decline of the fami- lies of the older world, already pointed out. We have no confusion of genera and species, and no shades of struc- ture to make dim their outlines." Now there is here an acknowledgment, in which all geologists accord, of a con- stant gradual approach to living types. Is not this, in itself, a fact speaking strongly for some simply natural procedure in the origin of the present tribes ? A change goes on from one set of forms to another, in the same way as one human generation is changed for another — namely, by the withdrawal of some and the addition of others, until at length the whole personnel of one age is superseded by that of another. The removal of old species is the result, by our critic's own showing, of law ; and laws for the ex- tinction of species are in operation at the present day. Can we well suppose the rise of the new species to be a phenomenon of an essentially different character ? for here is the whole question at issue. I say, no — any ideas I have ever acquired of philosophy, as an expression of our ascertainment of the order of nature or providence, forbid me to form such a conclusion. A " confusion of genera or species" is not to be presumed ; there is no need for a shading of structure to make dim their outlines. I suggest, that a line of organization, analogous to the pro- gress of the embryo of an elevated species, had passed in
68
EXPLANATIONS.
the course of time through its appointed stages of develop* ment, each of which is a small advance upon the preced ing, and the type of a form thenceforth to continue perma- nent. Each line stands apart. It may show shadings in a vertical direction, as between its reptilian and its mam- mal forms, but no true affinities connecting horizontally with the members of other lines. Our critic is here, there- fore, completely at fault. I meet him again, however, on special grounds. Many of the animals of the tertiary period are of large bulk. We have not only huge exam- ples of the pachyderm order, in which there are still exist- ing many bulky species, but we have equally vast crea- tures belonging to the rodent, the edentate, and other orders. These huge mammals are, indeed, the signal forms of this period, the forms by which the whole tertiary system is most distinguished. Now, if we take the living pachyderm order, we shall find that the largest species are of the lowest organization. For example, the elephant, with its short metatarsus, is a low form compared with the horse, in which the heel is raised so much above the ground. This is a progress of characters which could be shown in many other families. It is a progress which may be generally described as passing from the phocal form of the hind extremities, through the plantigrade, and ascend- ing to its ultimatum in the digitigrade. Now this progress is coincident with the distribution of the various lines of animals in physical geography, for while the first are ma- rine, the second are generally found in connection with shores, rivers, and low grounds, and the last (always the smallest) with the more varied surface of the interior. When we find, then, animals of the second kind most con- spicuous in this period, we have actual phenomena remark
OPINIONS OF CUVIER AND AGASSIZ. 69
ably in accordance with the scheme of development. We look in, as it were, upon the world, or at least, its chief zoological province, at the time when the lines had attained to the terrestrial mammal forms fitted for fluviatile and jungle life, and ere from these had yet sprung the whole of the smaller but more highly organized denizens of nature's common.
Our critic, having now run over the whole series of fos- sils, summons Cuvier, Agassiz, and Owen to express their opinions against the theory of development. The first " again and again affirms that the extinct fossil species were not produced by any continued natural organic law from other species." His French opponents tried, accord- ing to the reviewer, to overturn his conclusion by experi- ments in cross-breeding and the ransacking of ancient tombs. And they talked contemptuously of la cloture du siecle de Cuvier ; for which they fall under a reference to the fable of 'the ass and the dead lion. Now, I disclaim all responsibility for the experiments and language of the French theories on this subject. But, while I respect Cuvier, I must not concede too much even to his opinion. He was, after all, but a man, with the common liability to prejudices. I would, with all due reverence for the illus- trious Baron, remind my reviewer of an opinion which the former expressed in 1826, that a deluge had occurred about six thousand years ago, which broke down and made to disappear the countries which had before been inhabited by men, and the species of animals with which we are best acquainted. Ten years after this belief was expressed by Cuvier, I find Dr. Buckland quietly withdrawing his adherence to it in the Bridgewater Treatise. At this mo- ment it is not supported by a single geologist of the least
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repute. May not, then, the Baron Cuvier be wrong also in his opinion regarding the development of species ? So much, I trust, may be said without any disparagement to the author of the Regne Animal. The fact is, that the erroneous and imperfect ideas of great men often become an annoyance, from no fault on their part, but only be- cause the weak and narrow-minded are so apt, afterwards, to seize upon such ideas, and brandish them in the faces of advancing truths. For M. Agassiz I likewise entertain great respect ; but it happens that his liability to error is equally well established. The doctrines which he per- sisted for years in maintaining with respect to the con- stitution and movement of glaciers, are now all but deserted for the more accurate and philosophical deductions of Pro- fessor James Forbes. I may, therefore, receive the intel- ligence which the Neufchatel philosopher brings me re- garding the fossil fish, but be cautious in accepting as an infallible dictum what he is pleased to say on the compara- tively profound doctrine of organic development. Profes- sor Owen, whose modesty keeps pace with his fame, will hardly pretend to an infallibility which fails in two such noted instances. Besides, the difficulties which this great anatomist and others have found in sanctioning the deve- lopment theory, chiefly rest in mistaken assumptions with regard to the constitution of the animal kingdom. It is impossible, as they say, to make out a genealogy in a line of orders; but let a fresh naturalist, of equal standing, judge of the theory, after he has considered the animal kingdom in the arrangement now suggested, and I feel assured that its feasibility will receive a more favorable verdict.
The reviewer, however, would not abate one jot of his
RETRACTATION OF MR. SEDGWICK. 71
opinion, although Cuvier, Agassiz, and Owen were all against him ! If such be the state of his mind regarding Cuvier, with what face can he condemn St. Hilaire, who only does that towards the dead lion which our critic would also do, supposing the dead lion were equally opposed to his opinion ? The grounds for this strong assurance are in personal and immediate observation of facts. " We have examined," says he, " the old records ... in the spots where nature placed them, and we know their true historical meaning . . . We have visited in succession the tombs and charnel-houses of these old times, and we took with us the clew spun in the fabric of development ; but we found this clew no guide through these ancient labyrinths, and, sorely against our will, we were compelled to snap its thread . . . We now dare affirm that geology, not seen through the mist of any theory, but taken as a plain succession of monuments and facts, offers one firm cumulative argument against the hypothesis of develop- ment." What first strikes us in this declaration is the tone in which the writer speaks of his own convictions. Cuvier, Agassiz, Owen, may all be wrong ; but this wri- ter cannot. He has seen what he speaks of. Against " a dogmatical dictation contrary to the sober rules of sound philosophy" (his own words), there might have surely been some protection in the necessity of retractation to which the best geologists are occasionally reduced. For example, we have Professor Sedgwick, in 1831, undoing a theory he had formerly embraced :
" We now connect the gravel of the plains with the ele- vation of the newest system of mountains That
these statements militate against opinions but a few years sinoe held almost universally among us, cannot be denied.
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EXPLANATIONS.
But theories of diluvial gravel, like all other ardent gene- ralizations of an advancing science, must ever be regarded but as shifting hypotheses to be modified by every new fact, till at length they become accordant with all the phenomena of nature. In retreating, where we have advanced too far, there is neither compromise of dignity nor loss of strength ; for in doing this we partake but of the common fortune of every one who enters on a field of investigation like our own."
The contrast between the philosophic modesty of this passage, and the above extract from the Edinburgh re- viewer, must be very striking. The reader, who has seen the hollowness of so many of this writer's particular objec- tions to the development theory, can be little at a loss to form an estimate of the personal investigations of which he speaks. He seems to have yet to learn that the neces- sarily partial investigations which any single geologist may be able personally to make, can give no such amount of the requisite knowledge as may be acquired in another mode of study ; that the intellectual powers and prepara- tions of the personal inquirer ought also to be known, be- fore we can set such store even by that light which may be attained by his examinations. It is not uncommon for ordinary manners to boast of their knowledge of a coun- try from having sailed several times to one of its ports, and for private sentinels to pretend to a superior knowledge of a great battle, in one detachment of which they hap- pened to be engaged. Of such boastings and pretensions I must confess that I am strongly reminded by this writer.
The geological objections to the development theory have now been discussed, and to the public it must be left to
PHYSIOLOGICAL OBJECTIONS OF DR. CLARK. 73
decide the question, whether palaeontology is favorable or unfavorable to that scheme. I must not advert to the illus- trations which the theory derives from physiology, and the objections which have been made to them. The Edin- burgh reviewer occupies several of his pages with such objections, but, fortunately, they need not detain us long, as they come to little more than this, that he puts trust in Dr. Clark, of Cambridge, while I have resorted for the support of my general theory to the views advocated by other physiologists.* I may say that these views are pre-
* Dr. Whevvell (preface to Indications, Sfc.) joins the reviewer and others in reprobating the suggestions which have been made in the Vestiges, with regard to a similarity between certain crystalli- zations, as the figures produced by frost upon windows, and the Arbor Diana, to vegetable forms. The logical merits of the re- viewer's mind are here fully indicated, for what does he set down as a disproof of these as " traces of secondary means by which the Almighty deviser might establish" the forms of plants ? that such crystallizations grow by simple apposition of new matter,- and not from germs, as actual vegetables do ; the question at issue being merely, whether the electricity concerned in the crystallization might not have some similar effect in determining the forms of the vegetables. I may here remark that 1 am not alone in surmising some common root for these phenomena. In Leithead's Electricity (1837), the following passage occurs : — " The form of the route of free electricity is modified by the medium through which it passes, and also by the electric state of such medium, or of that of the rela- tive electrical condition of two bodies between which it is trans- mitted. If the medium through which it passes possesses a very inferior conducting power, it is obvious that a certain momentum must be requisite to enable the fluid to force its passage to a given distance, and there will be a point at which the momentum of the fluid and the resistance of the body will exactly counterbalance each other; but so soon as the electricity has again accumulated to a sufficient degree to overcome the resistance, it will again force its way in another direction, until it arrives at another point of equili-
74 EXPLANATIONS.
sented in my book as correctly as it was possible for me to give them, who am nothing but a general student: in one instance I have employed the language of a popular treatise (Dr. Lord's) — ridiculed by our reviewer as a book of no authority — merely because the ideas were there pre- sented in a peculiarly intelligible form. The general aim was, I can honestly declare, to convey the doctrine of the epigenesis of animals, as M. Serres calls it, as an illustra- tion of my subject, considering myself entitled to do so by the position which it has attained in the world. It is, of
brium. In this way, we may readily see the modus operandi of the electric fluid in imparting regular forms to bodies ; and it is highly probable that its action in this respect extends to the vegetable kingdom, and perhaps operates even on animals, from the time in which they exist in the embryo state. . . . Another fact in support of the opinion, that the distinctive forms of bodies are pro- duced by electrical action, is, that crystals, and the twigs and leaves of vegetables, all terminate in points or sharp edges, so that the electrical action can proceed no further in increasing the growth, or, in other words, in propelling fresh portions of matter for the extension of the plant, or the crystal, beyond the pointed or edged termination." In a letter of Mr. Crosse to Mr. Leithead, it is stated that, in one of his experiments, there grew, in the inside of an elec- trified jar filled with hydro-sulphuret of potash, a mineral fungus, three-fourths of an inch in length and one-fourth of an inch in diameter, " m the shape of a common trumpet-mouthed fungus, which is found on trees." " In one experiment," says Mr. Weekes, in a recent letter to myself, " a singularly beautiful elec- tro-vegetation was produced, a forest in miniature, which, by aid of a good lens, presented many extraordinary appearances, and con- tinued to interest me during many months." It may suit the re- viewer and others to scoff at such " resemblances;" but scoffing will not annul, in my mind, the apprehension that there is here some relation of a very interesting kind, the investigation of which may yet give us a deeper insight than we now enjoy in the mysteries of organic being.
EMBRY0TIC REPRESENTATIONS.
75
course, unfortunate for this, as it is for many other doc- trines, that it should have an opponent ; but this circum- stance is fortunately, on the other hand, no adequate ground of condemnation in the judgment of third parties. I leave, then, the general tenor of this portion of my re- viewer's objections, with the remark, that for the one authority which he has called into court, it would be easy to summon many as good on the other side ; for instance, Harvey, Grew, Lister, and Meckel. Our critic's own favorite authority — Mr. Owen — would give good evidence ; see his Letters on the Invertebrated Animals, where he says that man's embryotic metamorphoses would not be less striking than those of the butterfly, if subjected like them to observation — and then adds, that the human embryo is first vermiform, next stamped with the characters of the apodal fish, afterwards indicative of the enaliosaur, and so forth. There is another most respectable English physi- ologist— Dr. Roget — who, in his Bridgewater Treatise, ex- plicitly says, " that the animals which occupy the highest stations in each series possess, at the commencement of their existence, forms exhibiting a marked resemblance to those presented in the permanent condition of the lowest animals of the same series ; and that, during the progress of their development, they assume in succession the cha- racters of each tribe, corresponding to their consecutive order in the ascending chain." It is to what has been thus spoken of by such excellent men — what was, I be- lieve, first hinted at by Harvey, and afterwards shadowed forth by John Hunter — that this writer applies the appella- tion of " a monstrous scheme, from first to last nothing but a pile of wildly gratuitous hypotheses."
This reviewer and others have been eager to point out
76
EXPLANATIONS.
that " no anatomist has observed the shadow of any change assimilating the nascent embryo to any of the radiata, mol- lusca, or articulata. Thus are three whole classes [divi- sions] of the animal kingdom, passed over without any cor- responding fetal type, and in defiance of the law of de- velopment." The writer here states what is not true, if any faith is to be placed in one of the first authorities of the age, and one upon which he himself depends ; for have we not seen Mr. Owen on the last page affirming that the human embryo is first vermiform ? — this meaning the form of the worms, a portion of the class Annelides, in one of these lower divisions. That all these divisions or sub- kingdoms are not represented in the human embryo is an objection perfectly visionary, for it is not necessary that all should be involved in the ancestry, and therefore analo- gies to all are not to be looked for. It may be said, then, there is no true difficulty in this quarter.
Perhaps no part of the arguments for the development theory has been more misapprehended, or misrepresented, than this. It is continually said, that the embryo, at any of its particular stages, is not in reality the animal repre- sented by that stage. The Edinburgh reviewer remarks, with regard to the fish stage, " Were the embryo of a mammal thrown off at that time into water (of its own tem- perature), it could not support life for a moment." The brain of a child in the seventh month is also said to be not the brain of any of the inferior animals, but a true human brain. The truth is, no one ever pretended that there was such an identity. It is only said that there is a resem- blance in general character between the particular embry- otic stage of being, and the mature condition and form of the appropriate inferior animal. The particular adapta-
GERMS NOT IDENTICAL. 77
tions, and the character of vital maturity, are all wanting, and therefore it is that the embryo could not live, as the inferior animal represented, if separated from the parent, and really is not that inferior animal.
It may be well, before leaving this part of the subject, to advert to a special charge which this writer, and at least one other,* have brought forward : it is, that I assume, not only that the organic germs of all creatures are alike, but that they are identical. The Edinburgh Review brings a contradiction to this proposition from Dr. Clark. It is wholly unnecessary, for no such assumption was ever made by me. The phrase used in the book was, " Its primary positions [meaning the doctrines of embryonic development] are that the embryos of all animals are not distinguishably different from each other ;" which is a very different pro- position. In several other instances, propositions are thus misrepresented to afford the glory of a visionary refutation. For example : the idea that there being light in the planets, any inhabitants of these orbs may be presumed to have eyes, as eyes bear a relation to light, is met by him very gravely with the fact, left for him to discover, that animals have eyes before they are born !
I have now reviewed the vestiges of creation, presented in both the geological and physiological records, the former presenting memorials of the actual progression of species, in nearly such a conformity with the general arrange- ments of the organic kingdoms as we might expect in the present state of the science, and the latter affording us proofs — proofs, at least, satisfactory to many of the best anatomists of our age — of a plan of individual development,
* North American Review, April, 1845.
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EXPLANATIONS.
which may be called the living picture of the advance of species, during the vast ages chronicled by the sedimentary rocks. A third series of vestiges now remains for consi- deration— namely, those which hint at originations and modifications of organic beings in the current era.
The objections to the occasional production of organic beings, otherwise than ex ovo, do not appear to have been softened by the publication of my former volume. All reviewers, with the single exception of the British and Foreign Medical Review, have intimated their continued scepticism on this point. The experiment of Professor Schulze, of Berlin, with decaying organic matter floating in a flask to which common air was admitted, after passing through sulphuric acid, thereby being deprived of all ani- mal admixtures — an experiment which ended in the non- production of any animalcules or mould — is pointed to as conclusive. Explanations more or less plausible have also been offered for the origin of the entozoa, the parasites of civilisation, the pimelodes cyclopum, etc. I should fear to weary the reader with a new discussion of all these par- ticulars : for the sake of brevity, let me meet the call which the opponents of the development theory usually make, to give it the direct proof which would be afforded by show- ing one instance, either of the origin of life or the transmu- tation of species.
The objection of the Edinburgh reviewer, to the alleged transmutation of oats into rye, is that he believes it a fable. This is the opinion of one person, advanced without fact or argument to support it. Let us see, on the other hand, what a greater authority on botanical subjects than he — namely, Dr. Lindley — has stated on the same subject. " At the request," says this learned person, " of the Mar-
SPECIES A TEP.M, NOT A FACT.
79
qliis of Bristol, the Reverend Lord Arthur Hervey, in the year 1843, sowed a handful of oats, treated thefh in the manner recommended, by continually stopping the flower- ing stems, and the produce, in 1844, has been for the most part ears of a very slender barley, having much the ap- pearance of rye, with a little wheat, and some oats ; sam- ples of which are, by the favor of Lord Bristol, now before us." The learned writer then adverts to the " extraordi- nary, but certain fact, that in orchidaceous plants, forms just as different as wheat, barley, rye, and oats, have been proved by the most rigorous evidence, to be accidental variations of one common form, brought about no one knows how, but before our eyes, and rendered permanent by equally mysterious agency. Then, says Reason, if they occur in orchidaceous plants, why should they not also occur in corn plants 1 for it is not likely that such vagaries will be confined to one little group in the vegeta- ble kingdom ; it is more rational to believe them to be a part of the general system of creation . . . How can we be sure, that wheat, rye, oats, and barley, are not all ac- cidental off-sets from some unsuspected species ?"* The reader will now be partly able to judge of the value of the unsupported dictum of the reviewer.
There are many other facts that throw a strong light on transmutation, both of plants and animals. So far from there being any decisive proof against this theory, there is no settled conclusion at this moment amongst naturalists, as to what constitutes a species. " There is," says Pro- fessor Henslow, " no law whatever hitherto established, by which the limits of variation to a given species can be satis-
* Gardener's Chronicle, August, 1844.
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EXPLANATIONS.
factorily assigned, and until some such law be aiscovcred, we cannot expect precision in the details of systematic botany."* " We have agreed," says Bicheno, " that a species shall be that distinct form, originally so created, and producing, by certain laws of generation, others like itself. There is this inconvenience attending the use of it by naturalists, that it assumes as a fact, that which, in the present state of science, is in many cases a fit subject of inquiry ; namely, that species, according to our definition, do exist throughout nature. It is too convenient a term to be dispensed with, even as an assumption ; only care should he taken that we do not accept the abstract term-for the fact." ^ Mr. Westwood, speaking of insects, says, " In very exten- sive genera, the distinctions of species are so minute, that it requires the most practised eye to separate them ; and, indeed, there are some groups, the species of which are so intricately blended together, that no two entomologists are agreed as to their distinctness." According to Mr. Halde- man, author of a learned work on the fresh-water mollusks of America, " There are distinct species in that class — among the Unionidse, for example [and this is a remark applicable to other departments of the animal kingdom], actually differing less from each other than the known va- rieties of certain variable species, which a Lamarkian might suppose to be of so recent an origin, as not to have yet become settled in the possession of their proper diag- nostic characters. Indeed, notwithstanding the assumption to the contrary, by authors who have little practical ac- quaintance with the details of natural history, the proper discrimination between species and variety, is one of the
* Magazine of Zoology and Botany, i., 116. t Linnsean Transactions, xv., 482.
TRANSMUTATION OF PLANTS.
81
greatest difficulties which the naturalist has to encounter ; and he who is successful in this department is entitled to a rank which comparatively few can attain."*
Of the extent to which modifications may be carried by palpable external conditions, I may now supply a few il- lustrations. It is well known that fungi and lichens attain to very different appearances in different situations, in con- formity with different conditions. Fries, we are told, '■' asserts that out of the different states of one species (telephora sulphurea), more than eight distinct genera had been constructed by different authors. It would seem, then, that the absolute number of species among the fungi is not nearly so great as has been usually supposed ; and that the kind produced by a decomposing infusion, or a bed of decaying solid matter, will depend as much upon the influence of the material employed, as upon the germ itself which is the subject of i'2."f
Among the questions proposed by the Academy of Sci- ences at Haarlem, in 1839, was one upon the following subject — "According to some botanists, Algaj of a very simple structure, placed under favorable circumstances, develope and change into different plants, belonging to genera much more elevated in the scale of organic being ; although these same algae, in the absence of such favorable circumstances, would be fertile, and reproduce their primi- tive form.":}: I would ask if this is a point as yet settled in the negative. The original of our cabbage is well known to be a trailing sea-side plant, entirely different from the cabbage in appearance. The cardoon and arti-
* Boston Journal of Natural History, t Carpenter's Physiology, p. 62.
\ Charlesworth's Magazine of Natural History, il, 448. 5*
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EXPLANATIONS.
choke are now admitted to be one, and Mr. Darwin was assured by an intelligent farmer that he has seen, in a deserted garden, the latter plant relapsing into the former.
It is well known, that when fresh-water mollusks are exposed for a little time to an influx of the sea, those which can survive the change assume considerably different characters. In a fresh-water tertiary formation of the island of Cos, Professor Edward Forbes and Lieutenant Spratt found various fresh-water molluscan shells — palu- dina, neretina, melanopsis, etc. — which had passed through surprising modifications in the course of three successive groups of deposits, supposed to have been marked by in- creasing influxes of sea- water. " The lowermost species of each genus were smooth, those of the centre partially plicated, and those of the upper part strongly and regularly ribbed."* This was apparently a retrogression to marine types. The differences in the three cases were greater than those which naturalists usually consider as grounds of specific distinction.
Surely there are here ample evidences of species, or what are usually regarded as such, being variable under changed conditions. It will be said, these changes are all mere variations of specific forms, and the facts do nothing but show that that has been called species which is only va- riety. But where is this to have its limits ? If the cab- bage and sea-plant are to be now regarded as one species, it seems to me that we have to go very little further, to come to the lines of successive forms or stirpes, which my hypothesis suggests. This view becomes the more striking when we remember that any variations which we now see,
* Report of Proceedings of the British Association, 1845.— Lite- rary Gazette.
SIVATHSKIBM AND GIRAFFE.
S3
lake place within a space of time extremely small in com- parison with those which geology allows for its phenomena. " Although," says Mr. Haldeman, " we may not be able, artificially, to produce a change beyond a definite point, it would be a hasty inference to suppose that a physical agent acting gradually for ages, could not carry the varia- tion a step or two further."
I may here advert to a fallacy which has been one of the principal difficulties in the way of the supposition of every kind of transmutation. It is always taken for granted that the parental animal must be extinguished in consequence of the change. Thus we find a suggestion by M. St. Hilaire that the modern giraffe may be a modifi- cation of the sivatherium of the Indian tertiaries, met very complacently by a reference to the discovery of Dr. Fal- coner, that in these tertiaries, the giraffe is associated with the sivatherium. So also, the suggestion that the hare of Siberia, with its curtailed ears, shorter hind legs, and ab- sence of tail, may be a modification of the ordinary hare, has been answered by Professor Owen, with a reference to the fact, that the tailless hare (Lagomys Spelseus) is found as early in the tertiaries as any species of the true genus, Lepus.* Now it is entirely an assumption on the part of those who oppose the transmutation theory, that the origi- nal animal shall perish when the new one is produced ; and therefore the difficulty is entirely of their own making. The probable fact is that the modification takes place in an offshoot of the original tribe, which has removed into a dif- ferent set of circumstances, these circumstances being the cause of the change : thus there is no need to presume that
* British Fossil Mammalia and Birds, p. 215.
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EXPLANATIONS.
the original tribe is at all affected by any such modifica- tion. The case is precisely analogous to that of a colony. We see, for example, the New Englanders change from the original English type, without any necessary effect upon the parent stock. Just so might the giraffe be a changed sivatherium, and yet the sivatherium continue to exist. And in point of fact, there are many animals now living along with their supposed modified descendants. Unless, therefore, it could be proved that the supposed descendant actually preceded in date the animal from which it was said to have sprung, objections of this nature can be of no force. The reader will understand that I only ad- duce the instances of the sivatherium and hare for the sake of illustration, and without undertaking to show that those animals have actually had such modified descendants as may have been attributed to them. I would entreat the candid opponent of the transmutation theory to review the subject in the improved light in which it appears, with this most gratuitous assumption set aside.
With regard to the origination of new life from inorga- nic elements, the Broomfield experiment would be quite decisive, if any evidence could be admitted for what men are unwilling to believe. The Edinburgh reviewer writes two pages which appear to put the alleged fact much out of countenance ; and yet it is true that ridicule, which always proceeds upon assumption, forms their entire com- position. He states that specimens of the insect were sent to Paris, where they set a whole conclave of philosophers a-laughing, because they were found to contain ova. It did not occur to him that independent generation is what the development theory presumes of every animal family which may have ever had an origin otherwise than ex ovo.
THE ACARUS CROSSII.
85
Other specimens were sent to London, but there their fate was sealed by their being found to be not a new species, but one then abundant in the country. These circum- stances, with a few empty jests, satisfy the critic that there was no independent generation in the case. Against such a conclusion, proceeding upon mere supposition, I adduce careful experiment. During the last three years, Mr. Weekes, of Sandwich, has continued to subject solutions to electric action, and invariably found insects produced in these instances, while they as invariably failed to appear where the electric action was not employed, but every other condition fulfilled. The rigid care taken in these experiments to exclude vitiating circumstances, gives them a high claim to notice, and T therefore present, as an ap- pendix, two letters from Mr. Weekes upon the subject. They cannot fail to be read with interest, and the more so, as they exhibit a man pursuing the investigation of an im- portant natural fact under the most discouraging circum- stances. If this new presentment of the Acarus Crossii shall still excite ridicule, I can only regret the mood of mind from which that ridicule arises ; but the opposite party must excuse my attaching no importance "to any- thing besides fact and argument. These alleged pheno- mena are open, like all others, to the test of counter-expe- riment. Let them be subjected to it in the most rigid manner, and set aside in the case of failure. But to meet them merely with scoffs and jests, or at the most, certain wholly gratuitous assumptions as to a possibly vai'ious cause, is not philosophical, and therefore deserves no con- sideration.
Having thus presented vestiges of laws for the origina- tion and modification of organic being, I must protest
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EXPLANATIONS.
against proof of the existence of such laws being held in- dispensable to the development theory. The earth, we see, has been peopled for ages before man began to observe nature or chronicle his observations. The organic world attained what appears to us completeness, in remote ages. It is a thing done, as individual reproduction is done at the birth of the new creature. We are not, therefore, to ex- pect conspicuous examples of either a new origin of life or a modification of species at the present day. Though, therefore, not one unequivocal instance of such origin and such modification could be presented, it would say nothing positive against the hypothesis that species originated, and made a series of advances in general organization, by the efficacy of law, in times long antecedent to our historical period. We should still have to say that the evidence of such phenomena was to be looked for elsewhere, — namely, in the history of the progress of organic being as chroni- cled for us by geology, and in the history which physiology affords us of the progress of the individual embryo. See- ing, then, that plants and animals came into existence gra- dually, in the course of a vast period of time, and in a succession conforming generally to their grades in organi- zation, and the stages through which the embryo of one of the highest has to pass before it attains maturity, we might say that we had seen all that could well be expected in the case, and enough to establish a strong probability for the development theory. Nevertheless, it may be admit- ted that any evidence of the continued existence of the creative and modifying laws, is still desirable, for the sake of corroboration. And such is the light in which I regard the facts which we possess regarding variations of type, and the production of some of the lower plants and ani-
VESTIGES OF CREATIVE LAWS.
*1
mals by means independent of generation. As in the pro- gress of an individual being, even after birth, we see the laws which preside over reproduction operating still in a faint degree in the defective nutrition which stunts, and the favoring conditions which advance and glorify, the state of infancy and youth, so might we expect that the laws which originally spread the vegetable and animal kingdoms over the earth, would still, perhaps, be traceable as faintly at work, especially in those lower families where life and the modifiable quality are most abundantly im- parted. The evidence for the existence of such laws is patent to the exact observation which will give it philoso- phical certainty, and to such observation I trust it will, in time, be subjected. Meanwhile, I claim its being received as a provisional aid to the theory of development.
Thus closes my review of the objections which have been made to the evidences for an organic creation by law. Such a mode of that creation was, I said at the first, rendered likely by the manifestation of a presidency of law both in the physical arrangements of the universe and in the constitution of our own minds. It seemed to me that, with evidences of law in these things, we had a strong probability established that law had been the mode of the divine working in the whole system revealed to our senses and reason, throughout all ages of its existence. And I believed that we were called upon, not to grasp at every objection to this idea which could be conjured out of the darkness of our imperfect knowledge, as if to save us from a disrelished conclusion, but rather to look with candid minds into nature, and endeavor to discover in what we do know the traces of such an origin of organi-
88
EXPLANATIONS.
zation as might harmonize with the conceptions forced upon us from other quarters; trusting that there never could be any disadvantage from embracing that view which the balance of reason might show to be the nearest to truth. The question is, to which view does the balance now incline ? Whether is it most likely that the Deity produced Being and its many-staged theatre in the manner of order or law, or by any different mode of a more arbi- trary character ; whether, consequently, are we to regard him as ruling the affairs of the world in the manner of an invariable order or otherwise 1 I say likely — because we are not to expect on any such questions the absolute de- monstration which attends a mathematical problem or an unchallengeable writing. We must be content if we only can see a preponderance of reasons for regarding the uni- verse and its Author in one or other of those lights. To be prepared for a decision upon this question, it is proper that the reader should be presented with a sketch of the theory opposed to that of universal order.
When we set about describing this system, we are struck by finding it vague and unsteady, varying with every degree of intelligence in its votaries and every addi- tion made to science. The uneducated man regards the whole system of the world as resulting from, and depend- ing upon, the immediate working and guidance of an almighty being who acts in each case as may seem to him most meet, exactly as human creatures do. Persons of intelligence, again, usually admit a system of general laws, but for the most part entertain it under great reser- vations, or in connection with views totally inconsistent with it. We find Dr. Clark, for instance, admitting a course of nature as the "will of God r reducing certain
DR. WHEWELL's PALjETIOLOGICAL sciences. 89
effects in a regular and uniform manner," but, this will " being arbitrary [an assumption, as far as natural means of knowledge are concerned], is, he says, as easy to be altered at any time as to be preserved."
Others cut off particular provinces of nature as excep- tions from the plan of constant order. Whatever part is dubious or obscure, to mankind generally or to themselves in particular, there they rear the torn standard of the arbi- trary system of divine rule. Human volitions form such a region to many who know not that Quetelet has reduced these to mathematical formulae, and that one of our own most popular divines has written a Bridgewater Treatise, to show the predominance of natural law over mind, as a proof of the existence and wisdom of God. Some who give up this domain to law, find footing in other depart- ments of nature upon which science has not as yet poured any clear light. We shall presently see by what weak arguments such exceptions are maintained. Meanwhile, it must be noted as important, that all is uncertainty on this side of the question — a strong presumption, were there no other, against it.
One of the most remarkable reservations made of late years from the system of invariable order is that presented in Dr. Whewell's History of the Inductive Sciences. Ad- mitting that nature, as revealed to our senses, is a system of causation, this writer halts when he comes to consider the origin of language and of arts, the origin of species and formation of globes. These he calls palsetiological sciences, because, in his opinion, we have to seek for an an- cient and different class of causes, as affecting them, from any which are now seen operating. " In no palsetiological sciences," says he, " has man been able to arrive at a
90
EXPLANATIONS.
beginning which is homogeneous with the known course of events. We can, in such sciences, often go very far back, determine many of the remote circumstances of the past series of events, ascend to a point which seems to be near their origin, and limit the hypothesis respecting the origin itself; but philosophers have never demonstrated, and, so far as we can judge, probably never will be able to demonstrate, what was the primitive state of things from which the progressive course of the world took its first departure. In all these paths of research, when we travel far backwards, the aspect of the earlier portions becomes very different from that of the advanced part on which we now stand ; but in all cases the path is lost in obscurity as it is traced backwards to its starting point : it becomes not only invisible, but unimaginable ; it is not only an inter- ruption, but an abyss which interposes itself between us and any intelligible beginning of things."*
Here, we have the view of exceptions which is enter- tained by one of the chief writers of the day, and the superior of one of our greatest academical institutions. The professional position of Dr. Whewell may be held to imply that we should receive from him a view at once leaning to the philosophical, and accommodated as far as possible to the prepossessions expected in a large class of persons. It is remarkable, but not surprising, how weak is the banner which he has raised to stop our course to- wards a theory of universal arrangement by ordinary natural law.
The necessity alleged by Dr. Whewell for a different
* Philosophy of the Inductive Sciences, apud Indications of the Creator.
DR. WHEWELL'S VIEWS CONDEMNED.
9J
set of causes in the early times of our globe, and with regard to the formation of that globe, is, at the very first, liable to strong suspicion, as reminding us much of that well known propensity of nations to fill up the first chap- ters of their history with mythic heroes and giants. The subjects of investigation are remote from common research ; they are not, and never could have been, chronicled in the manner of modern facts ; we are in the regions of the comparatively unknown — hence, something more magnifi- cent or impressive than ordinary must be supposed. Such is the reasoning, or rather no-reasoning. The point at which extraordinary causes have to be supposed is evi- dently quite arbitrary, resting exactly on the limits of the knowledge existing at any time, and always flying further and further back, in proportion as our knowledge increases. Had Dr. Whewell been writing fifty years ago, he would of course have included among his palsetiological sci- ences, the formation of strata, and the intrusions of the granitic and trappean among the aqueous rocks, which in- genuity has since explained by existing causes ; — for there is not a single argument for his considering the for- mation of globes and origin of species as palsetiological, which would not have applied with equal force to these phenomena before the days of Pallas and Hutton. Against a theory of mere assumption — a reasoning from ignorance to ignorance — such considerations form serious objections. But let us come to closer argument. Let us inquire how the idea of a different set of causes for the more important of these phenomena, agrees with such exact knowledge as we have attained respecting them.
" According to the nebular hypothesis," says Dr. Whewell, "the formation of this our system of sun
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EXPLANATIONS.
planets, and satellites, was a process of the same kind aa
those which are still going on in the heavens
But . . the uniformitarian doctrine on this subject rests on most unstable foundations. We have as yet only very vague and imperfect reasonings to show that by such condensation a material system such as ours could result ; and the introduction of organized beings into such a ma- terial system is utterly out of the reach of our philosophy. Here . . therefore, we are led to regard the present order of the world as pointing towards an origin altogether of a different kind from anything which our material science can grasp." Because the nebular hypothesis rests on unstable foundations, and " nothing has been pointed out in the existing order of things which has any resemblance or analogy, of any valid kind, to that crea- tive energy which must be exerted in the production of new species," — therefore, according to Dr. Whewell, we are " driven to assume events not included in the course of nature" as having formerly taken place. Such is his rea- soning. Now let us call to mind a few of the laws ascer- tained to have been concerned in the cosmical arrange- ments, leaving for the meantime all that is doubtful in the nebular hypothesis entirely out of view. The proportion of the equatorial to the polar diameter of the earth is ex- actly what a fluid mass rotating at such a rate of speed would assume any day we might try the experiment. The relative distances of the planets have been deter- mined by the relation of two laws of matter, so thoroughly patent in their working to modern observation, that a mathematician could ascertain this their result and an- nounce it from his closet, although he never had heard of a planetary system in which it was exemplified. There
DR. WHEWELL's VIEWS CONDEMNED. 93
is, surely, here anything but a likelihood that different causes from those now existing and acting, were the im- mediate means of producing the cosmical arrangements. May we not rather say that, whatever may have been the details of the formation of globes, we possess ample proof that it was a phenomenon evolved by virtue of exactly the same system of order which we see still operating upon earth ? As to the origin of organic beings, our knowledge of geology comes to precisely a similar effect. Admitting that we see not now any such fact as the pro- duction of new species, we at least know that, while such facts were occurring upon earth, there were associated phenomena in progress, of a character perfectly ordinary. For example, when the earth received its first fishes, sand- stone and limestone were forming in the manner exem- plified a few years ago in the ingenious experiments of Sir James Hall : basaltic columns rose for the future won- der of man, according to the principle which Dr. Gregory Watt showed in operation before the eyes of our fathers ; and hollows in the igneous rocks were filled with crystals, precisely as they could now be by virtue of electric ac- tion, as shown within the last few years by Crosse and Becquerel. The seas obeyed the impulse of gentle breezes, and rippled their sandy bottoms as seas of the present day are doing ; the trees grew as now by favor of sun and wind, thriving in good seasons and pining in bad ; this, while the animals above fishes were yet to be created. The movements of the sea, the meteorological agencies, the disposition which we see in the generality of plants to thrive when heat and moisture were most abundant, were kept up in silent serenity, as matters of sim- ply natural order, throughout the whole of the ages which
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EXPLANATIONS.
saw reptiles enter in their various forms upon the sea and land. It was about the time of the first mammals, that the forest of the Dirt Bed was sinking in natural ruin amidst the sea sludge, as forests of the Plantagenets have been doing for several centuries upon the coast of Eng- land. In short, all the common operations of the physical world were going on in their usual simplicity, obeying that order which we still see governing them, while the supposed extraordinary causes were in sequisition for the develop- ment of the animal and vegetable kingdoms. There surely hence arises a strong presumption against any such causes. It becomes much more likely that the latter phenomena were evolved in the manner of law also, and that we only dream of extraordinary causes here, as men once dreamt of a special action of deity in every change of wind and the results of each season, merely because they did not know the laws by which the events in ques- tion were evolved.
The writer of the critique in the Edinburgh Review is another representative of opinion on this subject whose ideas are worthy of notice. These ideas are not very clear, but I shall endeavor to gather them from the various parts of his paper where they are expressed. He says of certain animals (p. 60) — " They were not called into being by any law of nature, but by a power above na- ture." If he means by a law of nature something inde- pendent of the Deity, I entirely concur with him. Most unquestionably, the animals resulted from a power, which is above nature, in the sense of its being the Author of nature. He adds — " They were created by the hand of God, and adapted to the conditions of the period." If he here means a special exertion of the powers of the Deity,
GENERAL VIEWS OF EDINBURGH REVIEWER.
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having a regard to special conditions, we part company, for my object is to show that animals were indebted for their gradations of advance to a law generally impressed by the Deity upon matter, and that their external pecu- liarities are owing immediately to the agency of those very conditions to which they are supposed to have been adapted. I contend that there was no more need for a special exertion to produce (for instance) mammalia, than there is for one to carry a human foetus on from the sixth to the seventh, or from the eighth to the ninth month. I had remarked in no irreverent spirit, but the contrary, that the supposition of frequent special exertion anthropo- morphises the Deity ; I find a similar idea expressed by one who will not be suspected of irreverence on such a subject, the pious and amiable Doddridge — " When we assert," says he, " a perpetual divine agency, we readily acknowledge that matters are so contrived as not to need a divine interposition in a different manner from that in which it had been constantly exerted. And it is most evident that an unremitting energy, displayed in such cir- cumstances, greatly exalts our idea of God, instead of de- pressing it ; and therefore, by the way, is so much the more likely to be true." The Edinburgh reviewer denies that there is any lowering of the divine character in sup- posing a system of special exertion. " The law of crea- tion," he says, " is the law of the Divine will, and nothing else besides. . . The fiat of the Almighty was suffi- cient at all times, and for all the phenomena of the uni- verse, material and moral."
" It may be true," he continues, " that in the concep- tion of the Divine mind there is no difference between the creation of dead matter and its unbending laws, and the
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creation of organic structures subservient to all the func- tions of individual life. But such views are, and must be, above our comprehension. . . Each organic structure is a miracle as incomprehensible as the creation of a plan- etary system ; and each structure is a microcosm related to all other worlds within the ken of sense ; yet governed by laws and revolving cycles within itself, and implied in the very conditions of its existence. What know we of the God of nature (we speak only of natural means), ex- cept through the faculties he has given us, rightly em- ployed on the materials around us 1 In this we rise to a conception of material inorganic laws, in beautiful har- mony and adjustment ; and they suggest to us the con- ception of infinite power and wisdom. In like manner we rise to a conception of organic laws — of means (often almost purely mechanical, as they seem to us, and their organic functions well comprehended) adapted to an end, — and that end only the well-being of a creature endowed with sensation and volition. Thus we rise to a concep- tion both of Divine power and Divine goodness ; and we are constrained to believe, not merely that all material law is subordinate to His will, but that he has also (in the way he allows us to see His works) so exhibited the attributes of His will, as to show himself to the mind of man as a personal and superintending God, concentrating his will on every atom of the universe." The reviewer then cen- sures the language used in rny book with respect to the idea of special creative efforts. " Does not our author," says he, " see that he binds the Divinity (on his dismal material scheme) in chains of fatalism as firmly as the Homeric gods were bound in the imagination of the blind old poet ? . . The material system may end in down-
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right atheism ; or, if not, it stops short in the undeviating sequence of second causes. . . Our view, on the con- trary, sees, from one end of the scale to the other, the ma- nifestation of a great principle of creation external to mat- ter— of final cause, proved by organic structures created in successive times, and adapted to changing conditions of the earth. It therefore gives us a personal and superin- tending God who careth for his creatures."
If such be the best view of the opposite theory which a clever scholar and a man of science of the present day can give, that theory must certainly be regarded as in a very unpromising condition. He is, we see, for fiats or effort adapted to special conditions. These may be, in the di- vine conception, identical with natural laws or the system of order ; but we cannot comprehend it. It is not given to our faculties to understand a matter so profound. Im- mediately after, he informs us that we have only these faculties to look to for information on this very subject ; and they tell us — what ? — that the world is a system of law ! law, however, subordinate to the divine will. Sure- ly, if our faculties cannot comprehend the point above stated, they must be equally unable to pronounce deci- sively upon points so abstruse as law being subordinate to will, and the attributes of that will showing us the Deity as a personal and superintending God. Were controver- sialists entitled thus to assume that the human faculties can pronounce upon one subject in their own way, but are struck powerless on approaching another, tending to an opposite conclusion, there would, of course, be an end of all argument. But even that exercise of the faculties which the reviewer admits of for his own purpose, by no means goes to the conclusion at which he arrives. He
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refers but to a small portion of the divine works, when he speaks of " organic structures created in successive times and adapted to the changing conditions of the earth." He cannot be permitted to assume that he has proved these to have been produced by special fiats or any other mode of special exertion, " in conformity with changed conditions:" on the contrary, his proposition is disjiroved, for we hear in many instances of conditions suitable for new beings, countless ages before the suitable beings make their ap- pearance, showing that such was not the principle to which we are solely to look for the genesis of animals. But, even though he were more successful on this point, he would still be required to show his theory of fiats, in har- mony with a system, the most important facts of which appear, on the contrary, to have taken their present forms and arrangements under the immediate agency of the " Unremitting Energy." As to results which may flow from any particular view which reason may show as the best supported, I must firmly protest against any assumed title in an opponent to pronounce what these are. The first object is to ascertain truth. No truth can be deroga- tory to the presumed fountain of all truth. The deroga- tion must lie in the erroneous construction which a weak human creature puts upon the truth. And practically it is the true infidel state of mind which prompts apprehen- sion regarding any fact of nature, or any conclusion of sound argument.
The ingenious Agassiz is equally disposed with Dr. Whewell and the Edinburgh Reviewer to except some part of nature as a domain for special intervention ; but he wishes the limits of that domain to be rigidly examined, and reprobates the idea that such inquiries are beyond our
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province. " If," says he, " it is an obligation on science to proclaim the intervention of a divine power in the de- velopment of the whole of nature, and if it is to that power alone that we must ascribe all things, it is not the less incumbent on science to ascertain what is the influence which physical forces, left to themselves, exercise in all natural phenomena, and what is the part of direct action which we must attribute to the supreme being, in the revolutions to which nature has been subjected. . . . It is now time for naturalists to occupy themselves like- . wise, in their domain, in inquiring within what limits we can recognize the traces of a <livine interposition, and within what limits the phenomena take place in conse- quence of a state of things immutably established from the beginning of the creation. Let it not be said that it is not given to man to sound these depths : the knowledge he has acquired of so many hidden mysteries in past ages, pro- mises more extended revelations. It is an error to which the mind, from a natural inclination to indolence, allows itself too easily to incline, to believe impossible what it would take some trouble to investigate. We generally would impose limits to our faculties, rather than increase their range by their exercise ; and the history of the sci- ences is present to tell us, that there are few of the great truths now recognized, which have not been treated as chi- merical and blasphemous before they were demonstrated."* Where men are so much perplexed between two oppo- site principles, led by science in the one direction and drawn by intellectual indolence or timidity in the other, it is not surprising to find them expressing opinions wholly
* Jameson's Journal, 1842.
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contradictory. Sir John Herschel some years ago an* nounced views strictly conformable to those subsequently taken of organic creation in my book. " For my part," said he, " I cannot but think it an inadequate conception of the Creator, to assume it as granted that his combina- tions are exhausted upon any one of the theatres of their former exercise, though, in this, as in all his other works, we are led, by all analogy, to suppose that he operates through a series of intermediate causes, and that, in con- sequence, the origination of fresh species, could it ever come under our cognizance, would be found to be a natural, in con- tradistinction to a miraculous process, — although we perceive no indications of any process actually in progress which is likely to issue in such a result." In his address to the British Association at Cambridge (1845), he said, with respect to my hypothesis of the first step of organic creation — " The transition from an inanimate crystal to a globule capable of such endless organic and intellectual develop- ment, is as great a step — as unexplained a one — as un- intelligible to us — and in any sense of the word as miracu- lous, as the immediate creation and introduction upon earth of every species and every individual would be !"
The reader will now be able to judge of the views op- posed to the theory of universal order. He observes that they are of no distinct unique character, but for the most part follow the measure of ignorance, and are maintained at the expense of consistency. It is not surprising that the idea of an organic creation by special exertion or fiat should be maintained by the advocates of these views, for it is one of the last obscure pieces of scientific ground on which they can show face. One after another, the pheno- mena of nature, like so many revolted principalities, have
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fallen under the dominion of order or law ; but here is one little province still faithful to the Boeotian government ; and as it is nearly the last, no wonder it is so vigorously de- fended. As, in the political world, however, men do not trust in the endurance of a dynasty which is reduced to a single city or nook of its dominions, so may we expect a speedy extinction to a doctrine which has been driven from every portion of nature but one or two limited fields. Several eminent authors of our age have even pronounced upon the question as already settled. " Our most deeply investigated views of the Divine Government," says the Rev. Dr. Pye Smith, " lead to the conviction that it is ex- ercised in the way of order, or what we usually call law. God reigns according to immutable principles, that is, by law, in every part of his kingdom — the mechanical, the intellectual, and the moral ; and it appears to be most clearly a position arising out of that fact, that a comprehen- sive germ which shall necessarily evolve all future develop- ments, down to the minutest atomic movements, is a more suitable attribution to the Deity, than the idea of a neces- sity for irregular interferences."*
In Blackwood's Magazine, a writer, understood to be a naturalist of distinguished ability, expresses himself in an equally decided manner : — " To reduce to a system the acts of creation, or the development of the several forms of animal life, no more impeaches the authorship of creation, than to trace the laws by which the world is upheld, and its phenomena perpetually renewed. The presumption naturally rises in the mind, that the same Great Being would adopt the same mode of action in both cases . . .
* Letter to Dr. Carpenter, appendix to Phil. Mag., xvi. (1840.)
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To a mind accustomed, as is every educated mind, to re- gard the operations of Deity as essentially differing from the limited, sudden, evanescent impulses of a human agent, it is distressing to be compelled to picture to itself, the power of God as put forth in any other manner than in those slow, mysterious, universal laws, which have so plainly an eternity to work in ; it pains the imagination to be obliged to assimilate those operations, for a moment, to the brief energy of a human will, or the manipulations of a human
hand There are still, indeed, some men of narrow
prejudices, who look upon every fresh attempt to reduce the phenomena of nature to general laws, and to limit those occasions on which it is necessary to conceive of a direct and separate interposition of divine power, as a fresh encroachment on the prerogatives of the Deity, or a con- cealed attack upon his very existence. And yet these very same men are daily appealing to such laws of the creation as have been already established for their great proofs of the existence and wisdom of God ! . . . " He adds,* " No, there is nothing atheistic, nothing irreligious, in the attempt to conceive creation, as well as reproduction, car- ried on by universal laws."*
There is, however, no more interesting or valuable tes- timony to universal causation than that presented in the System of Logic of Mr. Stuart Mill. If, in the following extract, we were to substitute the creation of organisms for human volitions, it would apply remarkably well to the state of the argument presented in the present volume :
" The conviction that phenomena have invariable laws, and follow with regularity certain antecedent phenomena,
* Review of Vestiges, Blackwood's Magazine, April, 1845.
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was only acquired gradually, and extended itself, as know- ledge advanced, from one order of phenomena to another, beginning with those whose laws were most accessible to observation. This progress has not yet attained its ulti- mate point ; there being still one class of phenomena [hu- man volitions], the subjection of which to invariable laws is not yet universally recognized. So long as any doubt bung over this fundamental principle, the various methods of induction which took that principle for granted could only afford results which were admissible conditionally; as showing what law the phenomenon under investigation must follow if it followed any fixed law at all. As, how- ever, when the rules of correct induction had been con- formed to, the result obtained never failed to be verified by all subsequent experience ; every such inductive operation had the effect of extending the acknowledged dominion of general laws, and bringing an additional portion of the ex- perience of mankind to strengthen the evidence of the uni- versality of the law of causation ; until now at length we are fully warranted in considering that law, as applied to all phenomena within the range of human observation, to stand on an equal footing in respect to evidence ivith the axioms of geometry itself
" I apprehend that the considerations which give, at the present day, to the proof of the law of uniformity of suc- cession as true of all phenomena without exception, this character of completeness and conclusiveness, are the fol- lowing : — First ; that we now knoiv it directly to be true of by far the greatest number of phenomena ; that there are none of which we know it not to be true, the utmost that can be said being, that of some we cannot positively, from direct evidence, affirm its truth ; while phenomenon after
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phenomenon, as they become he tier known to us, are constantly fussing from the latter class into the former ; and in all cases in which that transition has not yet taken place, the absence of direct proof is accounted for by the rarity or the ob- scurity of the phenomena, our deficient means of observing them, or the logical difficulties arising from the complica- tion of the circumstances in which they occur ; insomuch that, notwithstanding as rigid a dependence upon given conditions as exists in the case of any other phenomenon, it was not likely that we should be better acquainted with those conditions than we are. Besides this first class of considerations, there is a second, which still further corro- borates the conclusion, and from the recognition of which the complete establishment of the universal law may rea- sonably be dated. Although there are phenomena, the production and changes of which elude all our attempts to reduce them universally to any ascertained law ; yet in every such case, the phenomenon, or the objects concerned in it, are found in some instances to obey the known laws of nature. The wind, for example, is the type of uncertainty and caprice, yet we find it in some cases obeying with as much constancy as any phenomena in nature the law of the tendency of fluids to distribute themselves so as to equalize the pressure on every side of each of their parti- cles ; as in the case of the trade winds, and the monsoons. Lightning might once have been supposed to obey no laws ; but since it has been ascertained to be identical with elec- tricity, we know that the very same phenomenon, in some of its manifestations, is implicitly obedient to the action of fixed causes. I do not believe that there is now one object or event in all our experience of nature, within the bounds of the solar system at least, which has not either been ascertained
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by direct observation to follow laws of its own, or been proved to be exactly similar to objects and events, which, in more familiar manifestations, or on a more limited scale, follow strict laws : our inability to trace the same laws on the larger scale, and in the more recondite instances, being accounted for by the number and complication of the mo- difying causes, or by their inaccessibility to observation."*
The whole question, then, stands thus. For the theory of universal order — that is, order as presiding in both the origin and administration of the world — we have the testi- mony of a vast number of facts in nature, and this one in addition, — that whatever is reft from the domain of igno- rance and made undoubted matter of science, forms a new support to the same doctrine. The opposite view, once predominant, has been shrinking for ages into lesser space, and now maintains a footing only in a few departments of nature which happen to be less liable than others to a clear investigation. The chief of these, if not almost the only one, is the origin of the organic kingdoms. So long as this remains obscure, the supernatural will have a certain hold upon enlightened persons. Should it ever be cleared up in a way that leaves no doubt of a natural origin of plants and animals, there must be a complete revolution in the view which is generally taken of our relation to the Father of our being.
This prepares the way for a few remarks on the present state of opinion with regard to the origin of organic nature. The great difficulty here is the apparent determinateness of species. These forms of life being apparently un- changeable, or at least always showing a tendency to return to the character from which they may have * System of Logic, ii., 116.
6*
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diverged, the idea arises that there can have been no pro- gression from one to another ; each must have taken its special form, independently of other forms, directly from the appointment of the Creator. The Edinburgh reviewer says, " they were created by the hand of God and adapted to the conditions of the period." Now, it is, in the first place, not certain that species constantly maintain a fixed character, for we have seen that what were long considered as determinate species have been transmuted into others. Passing, however, from this fact, as it is not generally received among men of science, there remain some great difficulties in connexion with the idea of special creation. First, we should have to suppose, as pointed out in my former volume, a most startling diversity of plan in the divine workings, a great general plan or system of law in the leading events of world-making, and a plan of minute nice operation, and special attention in some of the mere details of the process. The discrepancy between the two con- ceptions is surely overpowering, when we allow ourselves to see the whole matter in a steady and rational light. There is, also, the striking fact of an ascertained historical progress of plants and animals in the order of their organi- zation ; marine and cellular plants and invertebrated animals first, afterwards higher examples of both. In an arbitrary system, we had surely no reason to expect mam- mals after reptiles ; yet in this order they came. The Edinburgh reviewer speaks of the animals as coming in adaptation to conditions ; but this is only true in a limited sense. The groves which formed the coal beds might have been a fitting habitation for reptiles, birds, and mam- mals, as such groves are at the present day ; yet we see none of the last of these classes, and hardly any trace of
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the two first in that period of the earth. Where the iguanodon lived, the elephant might have lived ; but there was no elephant at that time. The sea of the Lower Silurian era was capable of supporting fish ; but no fish existed. It hence forcibly appears that theatres of life must have lain unserviceable, or in the possession of a tenantry inferior to what might have enjoyed them, for many ages ; there surely would have been no such waste allowed, in a system where Omnipotence was working upon the plan of minute attention to specialties. The fact seems to denote that the actual procedure of the peopling of the earth was one of a natural kind requiring a long space of time for its evolution. In this supposition, the long exist- ence of land without land animals, and more particularly, without the noblest classes and orders, is only analogous to the fact, not nearly enough present to the minds of a civilized people, that to this day the bulk of the earth is a waste as far as man is concerned.
Another startling objection is in the infinite local varia- tion of organic forms. Did the vegetable and animal king- doms consist of a definite number of species adapted to peculiarities of soil and climate, and universally distributed, the fact would be in harmony with the idea of special exertion. But the truth is, that various regions exhibit variations altogether without apparent end or purpose. Professor Henslow enumerates forty-five distinct floras, or sets of plants upon the surface of the earth, notwithstanding that many of these would be equally suitable elsewhere. The animals of different continents are equally various, fe w species being the same in any two, though the general character may conform. The inference at present drawn from this fact is, that there must have been, to use the
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language of the Rev. Dr. Pye Smith, " separate and original creations, perhaps at different and respectively- distant epochs." It seems hardly conceivable that rational men should give an adherence to such a doctrine, when we think of wnat it involves. In the single fact that it necessitates a special fiat of the inconceivable Author of this sand-cloud of worlds to produce the flora of St. Helena, we read its more than sufficient condemnation. It surely harmonizes far better with our general ideas of nature, to suppose that, just as all else in this far-spread scene was formed by the laws impressed on it at first by its Author, so also was this. An exception presented to us in such a light, appears admissible only when we succeed in forbid- ding our minds to follow out those reasoning processes, to which, by another law of the Almighty, they tend, and for which they are adapted.
I feel that I have dwelt long enough on this part of the question, and yet there are a few geological facts which here call for special comment, and I am loath to overlook them. As is well known, most of the large carnivores and pachyderms of the late tertiary formations very closely resemble existing species ; but they are, nevertheless, determined to be distinct species by Professor Owen and other eminent authorities, in consideration of certain peculiarities. The peculiarities, are, in general, trifling, such as differences in the tubercles or groovings of the surface of teeth, or greater or less length of body or extremi- ties; but no matter of what the differences consist. Enough for the present that they are held by Mr. Owen and his friends to be of that character which are never passed in generation, but necessarily imply a new creation, a separate effort of divine power. Now it so happens that all the
PROFESSOR PICTET's OPINIONS. 109
tertiary species, or so-called species, have not been changed or extirpated. There is a Badger of the Miocene, which cannot be distinguished from the badger of the present day. Our existing Meles Taxus is, therefore, acknowledged by Mr. Owen to be " the oldest known species of mammal on the face of the earth." It is in like manner impossible to iliscover any difference between the present Wild Cat and that which lived in the bone caves with the hyaena, rhinoceros, and the tiger of the ante-drift era, all of which are said to be extinct species. So also the otter has sur- vived since an early period in the pliocene, while so many larger animals were shifted. The learned anatomist takes occasion from these facts to speak of a survival by small and weak species of geological changes, which have been accompanied by the extirpation of larger and more formi- dable animals of allied species. The inference from the facts and doctrines of this school is, that Divine Power has seen fit to change the species of elephants, rhinoceroses, tigers, and bears, using special miracles to introduce new ones, one with perhaps an additional tooth, another with a new tubercle or cusp on the third molar, and so forth, while he has seen no occasion for a similar interference with the otter, wild cat, and badger, which accordingly have been left undisturbed in their obscurity. Such may be the belief of men of science, anxious to support a theory; but assuredly it will never be received by any ordinary men of fair understandings who may be able to read and comprehend the works of Mr. Owen. It were too much for even a child's faith. Yet the Edinburgh reviewer, a member of this school, talks of " credulity !"
Perhaps it is but justice to Professor Pictet to notice his partial dissent from the reigning doctrine on this point.
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This learned person, finding that the elder alluvion of the Swiss valleys presents mammals identical with those which now live there, though accompanied by remains of ele- phants, and considering further that " the bats, shrews, moles, badgers, hares, &c, of the caverns appear to be identical with our own," concludes that the following was the order of events as they occurred in Europe : " The species now living, and some others, were created at the commencement of the diluvial epoch. Partial inundations and changes of temperature caused some of them to perish, such as the mammoth, the species of bear having an arched forehead, the hyasnas, the stag with gigantic horns, the rhinoceros, hippopotamus, &c. ; but the greater number of the species escaped these causes of destruction, and still live. Beside those which I have mentioned, and others which I have noticed in the body of my work, it is possible, for example, that the TJrsus Priscus may he the original of recent bears, etc. It may be said," he adds, " that this idea is opposed to the theory of the peculiarity of species in each formation, and to that of successive creations . . . but I cannot, on that account, refuse to adopt an explanation of facts which seems to me evident. The state of theoretical palaeontology is still too uncertain to allow of our attaching ourselves too strongly to this or that hypothesis. It is the study of facts which is essen- tial, and we must engage in that study unbiassed by pre- conceived ideas or particular systems."* I would com- mend this opinion of one of the first men of science in Europe to those British savans who regard a greater pli- cation of the enamel in a horse's tooth, or a ridge on a
* Traite Elementaire de Paleontologie ; L, 359, 1844. Apud Jameson's Journal, Oct., 1845.
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Ill
turbinated shell, or a spot on a butterfly's wing, as the proof of a special interference of that Deity who wheeled the orbs into space by a tranquil expression of his will. But M. Pictet must himself revise his opinions. He must quickly perceive that the rule which he lays down for there being no new creation since the diluvial epoch is equally conclusive against new creations at any anterior lime, There is a persistency of certain shells since the beginning of the tertiaries ; if, then, the moles and bad- gers be, in any degree, a proof that the present bear is a modification of the Ursus Priscus, so also are these shells a proof that all the present mammals are modifications of those of the eocene. Several shells, again, of the se- condary formation straggling into tertiaries, are not less conclusive, in rigid reasoning, that all the tertiary species were descended from the secondary, although the wide, unrepresented interval at that point, allowed of a greater transition of forms. In short the whole of the divisions constructed by geologists upon the supposition of exten- sive introductions of totally new vehicles of life, must give way before the application of this rule, and it must be seen that what they call new species are but variations upon the old. What, then, will remain to be done, before the theory of progressive development be adopted ? Only, as the candid reader will readily surmise, that the culti- vators of science should allow themselves to follow the dictates of reason, against the behests of prejudices un- worthy of them and of their age.
Time is the true key to difficulties regarding appear- ances of determinateness in species. Few of us, not even geologists, have ever realized in our minds the ex-
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tent of time which has elapsed since the beginning of life upon this globe. Mr. Lyell, without intending to favor the development theory, lends us powerful testimony on this point. After showing reason to believe, that about thirty-five thousand years have passed since the Niagara began to cut down the rock through which it flows, during which time the living mollusks, whether marine or ter- restrial, are proved to have undergone no change, he thus proceeds — " If such events can take place, while the zoology of the earth remains almost stationary and unal- tered, what ages may not be comprehended in those suc- cessive tertiary periods, during which the Flora and Fauna of the globe have been almost entirely changed ! Yet how subordinate a place in the long calendar of geological chronology do the successive tertiary periods themselves occupy ! How much more enormous a duration must we assign to many antecedent revolutions of the earth and its inhabitants ! No analogy can be found in the natural world to the immense scale of these divisions of past time, unless we contemplate the celestial spaces, which have been measured by the astronomer. Some of the nearest of these within the limits of the solar system, as, for ex- ample, the orbits of the planets, are reckoned by hundreds of millions of miles, which the imagination in vain en- deavors to grasp. Yet one of these spaces, such as the diameter of the earth's orbit, is regarded as a mere unit, a mere infinitesimal fraction of the distance which separates our sun from the nearest star. By pursuing still further the same investigations, we learn that there are luminous clouds, scarcely distinguishable by the naked eye, but resolvable by the telescope into clusters of stars, which are so much more remote, that the interval between our
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sun and Sirius may be but a fraction of this larger dis- tance. To regions of space of this higher order in point of magnitude, we may, probably, compare such an interval of time as that which divides the human epoch from the origin of the coralline limestone, over which the Niagara is pre- cipitated at the Falls. Many have been the successive revolutions in organic life, and many the vicissitudes in the physical geography of the globe, and often has sea been converted into land, since that rock was formed. The Alps, the Pyrenees, the Himalaya, have not only begun to exist as lofty mountain chains, but the solid ma- terials of which they are composed have been slowly ela- borated beneath the sea, within the stupendous interval of ages here alluded to."*
If time, to anything like the amount here insisted on, have really elapsed between the commencement of life and its attaining its highest forms, we must see that the space comprised by the life of an individual, or even that longer portion during which mankind have been watching the wonders of nature, is not sufficient to allow more than a chance of any transition of species being or having been observed, except perhaps in the humble fields where, as was formerly remarked, reproduction is most active and types least defined. If, however, even in our limited com- mand of this grand element, we can detect such transi- tions as those amongst the cerealia, or in a common in- fusion, may we not well suppose that much greater have taken place in the course of the vast series of ages here described ? Absolute proof on such a point may be im- possible ; but nearly the same effect may be reached, if
* Travels in North America, i., 52.
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we see vestiges of the supposed facts in living phenomena, just as we conclude upon the formation of stratified and igneous rocks from seeing similar phenomena, generally on a smaller scale, taking place before our eyes.
There is another mode of attaining the means of a tolerably definite conclusion, where perfect proof is unat- tainable. This is to show a portion or fraction of the entire phenomenon, in conformity with the hypothesis as to the whole. Now this can be done in the case under consideration. There are isolated parts of the earth, which we know to have become dry land more recently than others. Such is the Galapagos group of islands, situ- ated in the Pacific, between five and six hundred miles from the American coast. They are wholly of volcanic origin, and are considered by Mr. Darwin as having been raised out of the sea, " within a late geological period." Here, then, is a piece of the world undoubtedly younger, so to