Lamarck's Theory of Progression illustrated.—Class of Facts which give Color to it.—The Credulity of Unbelief.—M. Maillet and his Fish-birds.—Gradation not Progress.—Geological Argument.—The Present incomplete without the Past.—Intermediate Links of Creation.—Organisms of the Lower Old lied Sandstone.—The Pterichthys.—Its first Discovery.—Mr. Murchison's Decision regarding it.—Confirmed by that of Agassiz.—Description.—The several Varieties of the Fossil yet discovered.—Evidence of Violent Death in the Attitudes in which they are found.—The Coccosteus of the Lower Old Red.—Description.—Gradations from Crustacea to Fishes.—Habits of the Coccosteus.—Scarcely any Conception too extravagant for Nature to realize.
Mr. Lyell's brilliant and popular work, The Principles of Geology, must have introduced to the knowledge of most of my readers the strange theories of Lamarck. The ingenious foreigner, on the strength of a few striking facts, which prove that, to a certain extent, the instincts of species may be improved and heightened, and their forms changed from a lower to a higher degree of adaptation to their circumstances, has concluded that there is a natural progress from the inferior orders of being towards the superior; and that the offspring of creatures low in the scale in the present time, may hold a much higher place in it, and belong to different and nobler species, a few thousand years hence. The descendants of the ourang-outang, for instance, may be employed in some future age in writing treatises on Geology, in which they shall have to describe the remains of the quadrumana as belonging to an extinct order. Lamarck himself, when bearing home in triumph with him the skeleton of some huge salamander or crocodile of the Lias, might indulge, consistently with his theory, in the pleasing belief that he had possessed himself of the bones of his grandfather—a grandfather removed, of course, to a remote degree of consanguinity, by the intervention of a few hundred thousand great-greats. Never yet was there a fancy so wild and extravagant but there have been men bold enough to dignify it with the name of philosophy, and ingenious enough to find reasons for the propriety of the name.
The setting-dog is taught to set; he squats down and points at the game; but the habit is an acquired one—a mere trick of education. What, however, is merely acquired habit in the progenitor, is found to pass into instinct in the descendant: the puppy of the setting-dog squats down and sets untaught—the educational trick of the parent is mysteriously transmuted into an original principle in the offspring. The adaptation which takes place in the forms and constitution of plants and animals, when placed in circumstances different from their ordinary ones, is equally striking. The woody plant of a warmer climate, when transplanted into a colder, frequently exchanges its ligneous stem for a herbaceous one, as if in anticipation of the killing frosts of winter; and, dying to the ground at the close of autumn, shoots up again in spring. The dog, transported from a temperate into a frigid region, exchanges his covering of hair for a covering of wool; when brought back again to his former habitat, the wool is displaced by the original hair. And hence, and from similar instances, the derivation of an argument, good so far as it goes, for changes in adaptation to altered circumstances of the organization of plants and animals, and for the unprovability of instinct. But it is easy driving a principle too far. The elasticity of a common bow, and the strength of an ordinary arm, are fully adequate to the transmission of an arrow from one point of space to another point a hundred yards removed; but he would be a philosopher worth looking at, who would assert that they were equally adequate for the transmission of the same arrow from points removed, not by a hundred yards, but by a hundred miles. And such, but still more glaring, has been the error of Lamarck. Fie has argued on this principle of improvement and adaptation—which, carry it as far as we rationally may, still leaves the vegetable a vegetable, and the dog a dog—that, in the vast course of ages, inferior have risen into superior natures, and lower into higher races; that molluscs and zoöphytes have passed into fish and reptiles, and fish and reptiles into birds and quadrupeds; that unformed, gelatinous bodies, with an organization scarcely traceable, have been metamorphosed into oaks and cedars; and that monkeys and apes have been transformed into human creatures, capable of understanding and admiring the theories of Lamarck. Assuredly there is no lack of faith among infidels; their "vaulting" credulity o'erleaps revelation, and "falls on the other side." One of the first geological works I ever read was a philosophical romance, entitled Telliamed, by a M. Maillet, an ingenious Frenchman of the days of Louis XV. This Maillet was by much too great a philosopher to credit the scriptural account of Noah's flood; and yet he could believe, like Lamarck, that the whole family of birds had existed at one time as fishes, which, on being thrown ashore by the waves, had got feathers by accident; and that men themselves are but the descendants of a tribe of sea-monsters, who, tiring of their proper element, crawled up the beach one sunny morning, and, taking a fancy to the land, forgot to return.[H]
[H] Few men could describe better than Maillet. His extravagances are as amusing as those of a fairy tale, and quite as extreme. Take the following extract as an instance:—
"Winged or flying fish, stimulated by the desire of prey, or the fear of death, or pushed near the shore by the billows, have fallen among reeds or herbage, whence it was not possible for them to resume their flight to the sea, by means of which they had contracted their first facility of flying. Then their fins, being no longer bathed in the sea-water, were split, and became warped by their dryness. While they found, among the reeds and herbage among which they fell, any aliments to support them, the vessels of their fins, being separated, were lengthened and clothed with beards, or, to speak more justly, the membranes, which before kept them adherent to each other, were metamorphosed. The beard formed of these warped membranes was lengthened. The skin of these animals was insensibly covered with a down of the same color with the skin, and this down gradually increased. The little wings they had under their belly, and which, like their wings, helped them to walk in the sea, became feet, and served them to walk on land. There were also other small changes in their figure. The beak and neck of some were lengthened, and those of others shortened. The conformity, however, of the first figure subsists in the whole, and it will be always easy to know it. Examine all the species of fowls, large and small, even those of the Indies, those which are tufted or not, those whose feathers are reversed, such as we see at Damietta—that is to say, whose plumage runs from the tail to the head—and you will find species of fish quite similar, scaly or without scales. All species of parrots, whose plumages are so different, the rarest and the most singular-marked birds, are, conformable to fact, painted like them with black, brown, gray, yellow, green, red, violet color, and those of gold and azure; and all this precisely in the same parts where the plumages of those birds are diversified in so curious a manner."—Telliamed, p. 224, ed. 1750.
"How easy," says this fanciful writer, "is it to conceive the change of a winged fish, flying at times through the water, at times through the air, into a bird flying always through the air!" It is a law of nature, that the chain of being, from the lowest to the highest form of life, should be, in some degree, a continuous chain; that the various classes of existence should shade into one another, so that it often proves a matter of no little difficulty to point out the exact line of demarcation where one class or family ends, and another class or family begins. The naturalist passes from the vegetable to the animal tribes, scarcely aware, amid the perplexing forms of intermediate existence, at what point he quits the precincts of the one to enter on those of the other. All the animal families have, in like manner, their connecting links; and it is chiefly out of these that writers such as Lamarck and Maillet construct their system. They confound gradation with progress. Geoffrey Hudson was a very short man, and Goliath of Gath a very tall one, and the gradations of the human stature lie between. But gradation is not progress; and though we find full-grown men of five feet, five feet six inches, six feet, and six feet and a half, the fact gives us no earnest whatever that the race is rising in stature, and that at some future period the average height of the human family will be somewhat between ten and eleven feet. And equally unsolid is the argument, that from a principle of gradation in races would deduce a principle of progress in races. The tall man of six feet need entertain quite as little hope of rising into eleven feet as the short man of five; nor has the fish that occasionally flies any better chance of passing into a bird than the fish that only swims.
Geology abounds with creatures of the intermediate class: there are none of its links more numerous than its connecting links; and hence its interest, as a field of speculation, to the assertors of the transmutation of races. But there is a fatal incompleteness in the evidence, that destroys its character as such. It supplies in abundance those links of generic connection, which, as it were, marry together dissimilar races; but it furnishes no genealogical link to show that the existences of one race derive their lineage from the existences of another. The scene shifts, as we pass from formation to formation; we are introduced in each to a new dramatis personæ; and there exist no such proofs of their being at once different and yet the same, as those produced in the Winter's Tale, to show that the grown shepherdess of the one scene is identical with the exposed infant of the scene that went before. Nay, the reverse is well nigh as strikingly the case, as if the grown shepherdess had been introduced into the earlier scenes of the drama, and the child into its concluding scenes.
The argument is a very simple one. Of all the vertebrata, fishes rank lowest, and in geological history appear first. We find their remains in the Upper and Lower Silurians, in the Lower, Middle, and Upper Old Red Sandstone, in the Mountain Limestone, and in the Coal Measures; and in the latter formation the first reptiles appear. Fishes seem to have been the master existences of two great systems, mayhap of three, ere the age of reptiles began. Now fishes differ very much among themselves: some rank nearly as low as worms, some nearly as high as reptiles; and if fish could have risen into reptiles, and reptiles into mammalia, we would necessarily expect to find lower orders of fish passing into higher, and taking precedence of the higher in their appearance in point of time, just as in the Winter's Tale we see the infant preceding the adult. If such be not the case—if fish made their first appearance, not in their least perfect, but in their most perfect state—not in their nearest approximation to the worm, but in their nearest approximation to the reptile—there is no room for progression, and the argument falls. Now it is a geological fact, that it is fish of the higher orders that appear first on the stage, and that they are found to occupy exactly the same level during the vast period represented by five succeeding formations. There is no progression. If fish rose into reptiles, it must have been by sudden transformation—it must have been as if a man who had stood still for half a lifetime should bestir himself all at once, and take seven leagues at a stride. There is no getting rid of miracle in the case—there is no alternative between creation and metamorphosis. The infidel substitutes progression for Deity; Geology robs him of his god.
But no man who enters the geological field in quest of the wonderful, need pass in pursuit of his object from the true to the fictitious. Does the reader remember how, in Milton's sublime figure, the body of Truth is represented as hewn in pieces, and her limbs scattered over distant regions, and how her friends and disciples have to go wandering all over the world in quest of them? There is surely something very wonderful in the fact, that, in uniting the links of the chain of creation into an unbroken whole, we have in like manner to seek for them all along the scale of the geologist;—some we discover among the tribes first annihilated—some among the tribes that perished at a later period—some among the existences of the passing time. We find the present incomplete without the past—the recent without the extinct. There are marvellous analogies which pervade the scheme of Providence, and unite, as it were, its lower with its higher parts. The perfection of the works of Deity is a perfection entire in its components; and yet these are not contemporaneous, but successive: it is a perfection which includes the dead as well as the living, and bears relation, in its completeness, not to time, but to eternity.