Blainville, who by the way was the first to propose the word _palaeontology_, shows that the study of the great extinct mammals had for forty years been held in great esteem in Germany, before Faujas and Cuvier took up the subject in France. Two Frenchmen, also before 1789, had examined mammalian bones. Thus Bernard de Jussieu knew of the existence in a fossil state of the teeth of the hippopotamus.
Guettard[88] published in 1760 a memoir on the fossil bones of Aix en Provence. Lamanon (1780-1783)[89] in a beautiful memoir described a head, almost entire, found in the gypsum beds of Paris. Daubenton had also slightly antic.i.p.ated Cuvier"s law of correlation, giving "a very remarkable example of the mode of procedure to follow in order to solve these kinds of questions by the way in which he had recognized a bone of a giraffe whose skeleton he did not possess" (De Blainville).
"But it was especially in Germany, in the hands of Pallas, Camper, Blumenbach, anatomists and physicians, also those of Walch, Merck, Hollmann, Esper, Rosenmuller, and Collini (who was not, however, occupied with natural history), of Beckman, who had even discussed the subject in a general way (_De reductione rerum fossilium ad genera naturalia prototyporum--Nov. Comm. Soc. Scient.
Goettingensis_, t. ii.), that palaeontology applied to quadrupeds had already settled all that pertained to the largest species."
As early as 1764, Hollmann[90] had admirably identified the bones of a rhinoceros found in a bone-deposit of the Hartz, although he had no skeleton of this animal for comparison.
Pallas, in a series of memoirs dating from 1773, had discovered and distinguished the species of Siberian elephant or mammoth, the rhinoceros, and the large species of oxen and buffalo whose bones were found in such abundance in the quaternary deposits of Siberia; and, as Blainville says, if he did not distinguish the species, it was because at this epoch the question of the distinction of the two species of rhinoceros and of elephants, in the absence of material, could not be solved. This solution, however, was made by the Dutch anatomist Camper, in 1777, who had brought together at Amsterdam a collection of skeletons and skulls of the existing species which enabled him for the first time to make the necessary comparisons between the extinct and living species. A few years later (1780) Blumenbach confirmed Camper"s identification, and gave the name of _Elephas primigenius_ to the Siberian mammoth.
"Beckman" [says Blainville] "as early as 1772 had even published a very good memoir on the way in which we should consider fossil organic bodies; he was also the first to propose using the name _fossilia_ instead of _petrefacta_, and to name the science which studies fossils _Oryctology_. It was also he who admitted that these bodies should be studied with reference to the cla.s.s, order, genus, species, as we would do with a living being, and he compared them, which he called _prototypes_,[91] with their a.n.a.logues. He then pa.s.ses in review, following the zoological order, the fossils which had been discovered by naturalists. He even described one of them as a new species, besides citing, with an erudition then rare, all the authors and all the works where they were described. He did no more than to indicate but not name each species. Thus he was the means of soon producing a number of German authors who made little advance from lack of anatomical knowledge; but afterwards the task fell into the hands of men capable of giving to the newly created palaeontology a remarkable impulse, and one which since then has not abated."
Blumenbach,[92] the most eminent and all-round German anatomist and physiologist of his time, one of the founders of anthropology as well as of palaeontology, had meanwhile established the fact that there were two species of fossil cave-bear, which he named _Ursus spelaeus_ and _U.
arctoideus_. He began to publish his _Archaeologia telluris_,[93] the first part of which appeared in 1803.
From Blainville"s useful summary we learn that Blumenbach, mainly limiting his work to the fossils of Hanover, aimed at studying fossils in order to explain the revolutions of the earth.
"Hence the order he proposed to follow was not that commonly followed in treatises on oryctology, namely, systematic, following the cla.s.ses and the orders of the animal and vegetable kingdom, but in a chronological order, in such a way as to show that the cla.s.ses, so far as it was possible to conjecture with any probability, were established after or in consequence of the different revolutions of the earth.
"Thus, as we see, all the great questions, more or less insoluble, which the study of fossil organic bodies can offer, were raised and even discussed by the celebrated professor of Gottingen as early as 1803, before anything of the sort could have arisen from the essays of M. G. Cuvier; the errors of distribution in the cla.s.ses committed by Blumenbach were due to the backward state of geology."
The political troubles of Germany, which also bore heavily upon the University of Gottingen, probably brought Blumenbach"s labors to an end, for after a second "specimen" of his work, of less importance than the first, the _Archaeologia telluris_ was discontinued.
The French geologist Faujas,[94] who also published several articles on fossil animals, ceased his labors, and now Cuvier began his memorable work.
The field of the labors and triumphs of palaeontology were now transferred to France. We have seen that the year 1793, when Lamarck and Geoffroy Saint-Hilaire were appointed to fill the new zoological chairs, and the latter had in 1795 called Cuvier from Normandy to Paris, was a time of renascence of the natural sciences in France. Cuvier began a course of lectures on comparative anatomy at the Museum of Natural History. He was more familiar than any one else in France with the progress in natural science in Germany, and had felt the stimulus arising from this source; besides, as Blainville stated, he was also impelled by the questions boldly raised by Faujas in his geological lectures, who was somewhat of the school of Buffon. Cuvier, moreover, had at his disposition the collection of skeletons of the Museum, which was frequently increased by those of the animals which died in the menagerie. With his knowledge of comparative anatomy, of which, after Vicq-d"Azyr, he was the chief founder, and with the gypsum quarry of Montmartre, that rich cemetery of tertiary mammals, to draw from, he had the whole field before him, and rapidly built up his own vast reputation and thus added to the glory of France.
His first contribution to palaeontology[95] appeared in 1798, in which he announced his intention of publishing an extended work on fossil bones of quadrupeds, to restore the skeletons and to compare them with those now living, and to determine their relations and differences; but, says Blainville, in the list of thirty or forty species which he enumerates in his tableau, none was apparently discovered by him, unless it was the species of "dog" of Montmartre, which he afterward referred to his new genera Palaeotherium and Anaplotherium. In 1801 (le 26 brumaire, an IX.) he published, by order of the Inst.i.tut, the programme of a work on fossil quadrupeds, with an increased number of species; but, as Blainville states, "It was not until 1804, and in tome iii. of the _Annales du Museum_, namely, more than three years after his programme, that he began his publications by fragments and without any order, while these publications lasted more than eight years before they were collected into a general work"; this "_corps d"ouvrage_" being the _Oss.e.m.e.ns fossiles_, which was issued in 1812 in four quarto volumes, with an atlas of plates.
It is with much interest, then, that we turn to Cuvier"s great work, which brought him such immediate and widespread fame, in order to see how he treated his subject. His general views are contained in the preliminary remarks in his well-known "Essay on the Theory of the Earth"
(1812), which was followed in 1821 by his _Discours sur les Revolutions de la Surface du Globe_.
It was written in a more attractive and vigorous style than the writings of Lamarck, more elegant, concise, and with less repet.i.tion, but it is dest.i.tute of the philosophic grasp, and is not the work of a profound thinker, but rather of a man of talent who was an industrious collector and accurate describer of fossil bones, of a high order to be sure, but a.n.a.lytical rather than synthetical, of one knowing well the value of carefully ascertained and demonstrated facts, but too cautious, if he was by nature able to do so, to speculate on what may have seemed to him too few facts. It is also the work of one who fell in with the current views of the time as to the general bearing of his discoveries on philosophy and theology, believing as he did in the universality of the Noachian deluge.
Like Lamarck, Cuvier independently made use of the comparative method, the foundation method in palaeontology; and Cuvier"s well-known "law of correlation of structures," so well exemplified in the vertebrates, was a fresh, new contribution to philosophical biology.
In his _Discours_, speaking of the difficulty of determining the bones of fossil quadrupeds, as compared with fossil sh.e.l.ls or the remains of fishes, he remarks:[96]
"Happily comparative anatomy possessed a principle which, well developed, was capable of overcoming every difficulty; it was that of the correlation of forms in organic beings, by means of which each kind of organism can with exact.i.tude be recognized by every fragment of each of its parts.--Every organized being," he adds, "forms an entire system, unique and closed, whose organs mutually correspond, and concur in the same definite action by a reciprocal reaction. Hence none of these parts can change without the other being also modified, and consequently each of them, taken separately, indicates and produces (_donne_) all the others.
"A claw, a shoulder-blade, a condyle, a leg or arm-bone, or any other bone separately considered, enables us to discover the kind of teeth to which they have belonged; so also reciprocally we may determine the form of the other bones from the teeth. Thus, commencing our investigation by a careful survey of any one bone by itself, a person who is sufficiently master of the laws of organic structure can reconstruct the entire animal. The smallest facet of bone, the smallest apophysis, has a determinate character, relative to the cla.s.s, the order, the genus, and the species to which it belongs, so that even when one has only the extremity of a well-preserved bone, he can, with careful examination, a.s.sisted by a.n.a.logy and exact comparison, determine all these things as surely as if he had before him the entire animal."
Cuvier adds that he has enjoyed every kind of advantage for such investigations owing to his fortunate situation in the Museum of Natural History, and that by a.s.siduous researches for nearly thirty years[97]
he has collected skeletons of all the genera and sub-genera of quadrupeds, with those of many species in certain genera, and several individuals of certain species. With such means it was easy for him to multiply his comparisons, and to verify in all their details the applications of his laws.
Such is the famous law of correlation of parts, of Cuvier. It could be easily understood by the layman, and its enunciation added vastly to the popular reputation and prestige of the young science of comparative anatomy.[98] In his time, and applied to the forms occurring in the Paris Basin, it was a most valuable, ingenious, and yet obvious method, and even now is the princ.i.p.al rule the palaeontologist follows in identifying fragments of fossils of any cla.s.s. But it has its limitations, and it goes without saying that the more complete the fossil skeleton of a vertebrate, or the remains of an arthropod, the more complete will be our conception of the form of the extinct organism. It may be misleading in the numerous cases of convergence and of generalized forms which now abound in our palaeontological collections. We can well understand how guarded one must be in working out the restorations of dinosaurs and fossil birds, of the Permian and Tria.s.sic theromorphs, and the Tertiary creodonts as compared with existing carnivora.
As the late O. C. Marsh[99] observed:
"We know to-day that unknown extinct animals cannot be restored from a single tooth or claw unless they are very similar to forms already known. Had Cuvier himself applied his methods to many forms from the early tertiary or older formations he would have failed. If, for instance, he had had before him the disconnected fragments of an eocene tillodont he would undoubtedly have referred a molar tooth to one of his pachyderms, an incisor tooth to a rodent, and a claw bone to a carnivore. The tooth of a Hesperornis would have given him no possible hint of the rest of the skeleton, nor its swimming feet the slightest clue to the ostrich-like sternum or skull. And yet the earnest belief in his own methods led Cuvier to some of his most important discoveries."
Let us now examine from Cuvier"s own words in his _Discours_, not relying on the statements of his expositors or followers, just what he taught notwithstanding the clear utterances of his older colleague, Lamarck, whose views he set aside and either ignored or ridiculed.[100]
He at the outset affirms that nature has, like mankind, also had her intestine wars, and that "the surface of the globe has been much convulsed by successive revolutions and various catastrophes."
As first proof of the revolutions on the surface of the earth he instances fossil sh.e.l.ls, which in the lowest and most level parts of the earth are "almost everywhere in such a perfect state of preservation that even the smallest of them retain their most delicate parts, their sharpest ridges, and their finest and tenderest processes."
"We are therefore forcibly led to believe not only that the sea has at one period or another covered all our plains, but that it must have remained there for a long time and in a state of tranquillity, which circ.u.mstance was necessary for the formation of deposits so extensive, so thick, in part so solid, and filled with the exuviae of aquatic animals."
But the traces of revolutions become still more marked when we ascend a little higher and approach nearer to the foot of the great mountain chains. Hence the strata are variously inclined, and at times vertical, contain sh.e.l.ls differing specifically from those of beds on the plains below, and are covered by horizontal later beds. Thus the sea, previous to the formation of the horizontal strata, had formed others, which by some means have been broken, lifted up, and overturned in a thousand ways. There had therefore been also at least one change in the basin of that sea which preceded ours; it had also experienced at least one revolution.
He then gives proofs that such revolutions have been numerous.
"Thus the great catastrophes which have produced revolutions in the basins of the sea were preceded, accompanied, and followed by changes in the nature of the fluid and of the substances which it held in solution, and when the surface of the seas came to be divided by islands and projecting ridges, different changes took place in every separate basin."
We now come to the Cuvierian doctrine _par excellence_, one in which he radically differs from Lamarck"s views as to the genetic relations between the organisms of successive strata.
"Amid these changes of the general fluid it must have been almost impossible for the same kind of animals to continue to live, nor did they do so in fact. Their species, and even their genera, change with the strata, and although the same species occasionally recur at small distances, it is generally the case that the sh.e.l.ls of the ancient strata have forms peculiar to themselves; that they gradually disappear till they are not to be seen at all in the recent strata, still less in the existing seas, in which, indeed, we never discover their corresponding species, and where several even of their genera are not to be found; that, on the contrary, the sh.e.l.ls of the recent strata resemble, as regards the genus, those which still exist in the sea, and that in the last formed and loosest of these strata there are some species which the eye of the most expert naturalists cannot distinguish from those which at present inhabit the ocean.
"In animal nature, therefore, there has been a succession of changes corresponding to those which have taken place in the chemical nature of the fluid; and when the sea last receded from our continent its inhabitants were not very different from those which it still continues to support."
He then refers to successive irruptions and retreats of the sea, "the final result of which, however, has been a universal depression of the level of the sea."
"These repeated irruptions and retreats of the sea have neither been slow nor gradual; most of the catastrophes which have occasioned them have been sudden."
He then adds his proofs of the occurrence of revolutions before the existence of living beings. Like Lamarck, Cuvier was a Wernerian, and in speaking of the older or primitive crystalline rocks which contain no vestige of fossils, he accepted the view of the German theorist in geology, that granites forming the axis of mountain chains were formed in a fluid.
We must give Cuvier the credit of fully appreciating the value of fossils as being what he calls "historical doc.u.ments," also for appreciating the fact that there were a number of revolutions marking either the incoming or end of a geological period; but as he failed to perceive the unity of organization in organic beings, and their genetic relationship, as had been indicated by Lamarck and by Geoffroy St. Hilaire, so in geological history he did not grasp, as did Lamarck, the vast extent of geological time, and the general uninterrupted continuity of geological events. He was a.n.a.lytic, thoroughly believing in the importance of confining himself to the discovery of facts, and, considering the mult.i.tude of fantastic hypotheses and suggestions of previous writers of the eighteenth century, this was sound, sensible, and thoroughly scientific. But unfortunately he did not stop here.
Master of facts concerning the fossil mammals of the Paris Basin, he also--usually cautious and always a shrewd man of the world--fell into the error of writing his "theory of the world," and of going to the extreme length of imagining universal catastrophes where there are but local ones, a universal Noachian deluge when there was none, and of a.s.suming that there were at successive periods thoroughgoing total and sudden extinctions of life, and as sudden recreations. Cuvier was a natural leader of men, a ready debater, and a clear, forcible writer, a man of great executive force, but lacking in insight and imagination; he dominated scientific Paris and France, he was the law-giver and autocrat of the laboratories of Paris, and the views of quiet, thoughtful, profound scholars such as Lamarck and Geoffroy St. Hilaire were disdainfully pushed aside, overborne, and the progress of geological thought was arrested, while, owing to his great prestige, the rising views of the Lamarckian school were nipped in the bud. Every one, after the appearance of Cuvier"s great work on fossil mammals and of his _Regne Animal_, was a Cuvierian, and down to the time of Lyell and of Charles Darwin all naturalists, with only here and there an exception, were p.r.o.nounced Cuvierians in biology and geology--catastrophists rather than uniformitarians. We now, with the increase of knowledge of physical and historical geology, of the succession of life on the earth, of the unity of organization pervading that life from monad to man all through the ages from the Precambrian to the present age, know that there were vast periods of preparation followed by crises, perhaps geologically brief, when there were widespread changes in physical geography, which reacted on the life-forms, rendering certain ones extinct, and modifying others; but this conception is entirely distinct from the views of Cuvier and his school,[101] which may, in the light of our present knowledge, properly be deemed not only totally inadequate, but childish and fantastic.
Cuvier cites the view of Dolomieu, the well-known geologist and mineralogist (1770-1801), only, however, to reject it, who went to the extent of supposing that "tides of seven or eight hundred fathoms have carried off from time to time the bottom of the ocean, throwing it up in mountains and hills on the primitive valleys and plains of the continents" (Dolomieu in _Journal de Physique_).
Cuvier met with objections to his extreme views. In his discourse he thus endeavors to answer "the following objection" which "has already been stated against my conclusions":
"Why may not the non-existing races of mammiferous land quadrupeds be mere modifications or varieties of those ancient races which we now find in the fossil state, which modifications may have been produced by change of climate and other local circ.u.mstances, and since raised to the present excessive differences by the operation of similar causes during a long succession of ages?
"This objection may appear strong to those who believe in the indefinite possibility of change of forms in organized bodies, and think that during a succession of ages, and by alternations of habits, all the species may change into each other, or one of them give birth to all the rest. Yet to these persons the following answer may be given from their own system: If the species have changed by degrees, as they a.s.sume, we ought to find traces of this gradual modification. Thus, between the Palaeotherium and the species of our own days, we should be able to discover some intermediate forms; and yet no such discovery has ever been made. Since the bowels of the earth have not preserved monuments of this strange genealogy, we have a right to conclude that the ancient and now extinct species were as permanent in their forms and characters as those which exist at present; or, at least, that the catastrophe which destroyed them did not have sufficient time for the production of the changes that are alleged to have taken place."
Cuvier thus emphatically rejects all idea that any of the tertiary mammals could have been the ancestral forms of those now existing.
"From all these well-established facts, there does not seem to be the smallest foundation for supposing that the new genera which I have discovered or established among extraneous fossils, such as the _palaeotherium_, _anaplotherium_, _megalonynx_, _mastodon_, _pterodactylis_, etc., have ever been the sources of any of our present animals, which only differ as far as they are influenced by time or climate. Even if it should prove true, which I am far from believing to be the case, that the fossil elephants, rhinoceroses, elks, and bears do not differ further from the present existing species of the same genera than the present races of dogs differ among themselves, this would by no means be a sufficient reason to conclude that they were of the same species; since the races or varieties of dogs have been influenced by the trammels of domestication, which these other animals never did and indeed never could experience."[102]
The extreme views of Cuvier as to the frequent renewal and extinction of life were afterward (in 1850) carried out to an exaggerated extent by D"Orbigny, who maintained that the life of the earth must have become extinct and again renewed twenty-seven times. Similar views were held by Aga.s.siz, who, however, maintained the geological succession of animals and the parallelism between their embryonic development and geological succession, the two foundation stones of the biogenetic law of Haeckel.
But immediately after the publication of Cuvier"s _Oss.e.m.e.ns fossiles_, as early as 1813, Von Schlotheim, the founder of vegetable palaeontology, refused to admit that each set of beds was the result of such a thoroughgoing revolution.[103]
At a later date Bronn "demonstrated that certain species indeed really pa.s.sed from one formation to another, and though stratigraphic boundaries are often barriers confining the persistence of some form, still this is not an absolute rule, since the species in nowise appear in their entirety."[104] At present the persistence of genera like Saccamina, Lingula, Ceratodus, etc., from one age to another, or even through two or more geological ages, is well known, while _Atrypa reticulatus_, a species of world-wide distribution, lived from near the beginning of the Upper Silurian to the Waverly or beginning of the Carboniferous age.
Such were the views of the distinguished founder of vertebrate palaeontology. When we compare the _Hydrogeologie_ of Lamarck with Cuvier"s _Discours_, we see, though some erroneous views, some very fantastic conceptions are held, in common with others of his time, in regard to changes of level of the land and the origin of the crystalline rocks, that it did contain the principles upon which modern palaeontology is founded, while those of Cuvier are now in the limbo--so densely populated--of exploded, ill-founded theories.