An Expository Outline of the "Vestiges of the Natural History of Creation" / With a Notice of the Author's "Explanations:" A Sequel to the Vestiges

by S. Laing

Upon some of the chief points here involved, it may be remarked that the most eminent physiologists are not agreed; they are not agreed that animals can be arranged in a series, passing from lower to higher; nor that animals of a higher kind in the embryo state pass through the successive stages of the lower kinds; the character of these stages, in the asserted doctrine, being taken from the brain and heart, and man being the highest point of the series. There are physiologists too who deny that the brain of the human embryo at any period, however early, resembles the brain of any mollusk or of any articulata. It never, they assert, passes through a stage comparable or analogous to a permanent condition of the same organ in any invertebrate animal; and in like manner the spinal cord in the human vertebræ at no period agrees with the corresponding part of the lower kind of animals. The moment it becomes visible in the human embryo, it is entirely dorsal in position; while in mollusks and articulatas a great part, or nearly the whole, is ventral. The same is true of the heart, or centre of the vascular system, which has always a different relative position in the great nervous centre in the human embryo from what it has in any articulate animal, and in most mollusks.

A second position in the Vestiges appears not to have been established—namely, as to the uniform geological arrangement of different organic structures. It is not true that only the lowest forms of animal life are found in the lowest fossiliferous rocks, and that the more complicated structures are gradually and exclusively developed among the higher bands in what might be called a natural ascending scale. On the contrary, the predaceous cephalopods and the highly organized crustaceous are among the oldest fossils. Such appears to be the order of nature as evidenced by facts, and it must be admitted, however repugnant to preconceived notions or mere mortal conjectural amendments.

In the third place the evidence seems to preponderate in favour of permanency of species. There can be no doubt that both plants and animals may, by the influence of breeding, and of external agents operating upon their constitution, be greatly modified, so as to give rise to varieties and races different from what before existed. But there are limits to such modifications, as in the different kind and breed of dogs; and no organized beings can, by the mere working of natural causes, be made to pass from the type of one species to that of another. A wolf by domestication, for example, can never become a dog, nor the ourang-outang by the force of external circumstances be brought within the circle of the human species.

In this opinion Mr. LYELL, Dr. PRICHARD, and Mr. LAWRENCE, concur. The general conclusion at which they have arrived is, that there is a capacity in all species to accommodate themselves to a certain extent to a change of external circumstances; this extent varying greatly according to the species. There may thus be changes of appearance or structure, and some of these changes are transmissible to the offspring; but the mutations thus superinduced are governed by certain laws, and confined within certain limits. Indefinite divergence from the original type is not possible, and the extreme limit of possible variation may usually be reached in a short period of time; in short, Professor WHEWELL concludes (Indications of Creation, p. 56), that every species has a real existence in nature, and a transmutation from one to another does not exist. Thus for example, CUVIER remarks that, notwithstanding all the differences of age, appearance and habits, which we find in the dogs of various races and countries, and though we have (in the Egyptian mummies) skeletons of this animal as it existed 3,000 years ago, the relation of the bones to each other remains essentially the same; and with all the varieties of their shape and size, there are characters which resist all the influences, both of external nature, of human intercourse, and of time.

What varieties, again, in the forms of the different breeds of horses and horned cattle; racers, hunters, coach horses, dray horses, and ponies; short-horns and long-horns, Devons and Herefords, polled galloways and Shetlands; how unlike are the unimproved breeds of cattle as they existed a century ago before the march of agricultural improvement began, and how different were most of these as then existing in what may be called the normal state from the wild cattle produced in Chillington Park. It has been found, however, when external and artificial conditions are removed, and these different breeds are allowed to run wild, as in the Pampas and Australia, no matter what the diversity of size, shape, and colour of the domestic breeds, they reverted in their wild state, in these respects, to their primitive types.

So again with regard to cultivated vegetables and flowers. How different are the species of the red cabbage and the cauliflower; who would have expected them to be varieties of the wild brassica oleracea? Yet from that they have been derived by cultivation. They have, however, a tendency like animals to revert to the original type, or, in the gardener's phrase, to degenerate, which it requires the utmost care on his part to counteract. When left to a state of nature, they speedily lose their acquired forms, properties and character, and regain those of the original species.

If species be permanent—if no education or training can educe new kinds—if the higher classes of animals are not the results of meliorations of the lower—whence did they come? This question we are not bound to answer. It might be as reasonably asked, whence did the lower classes come? Geology, like other sciences, does not conduct us to the beginning, it only takes up creation at certain ulterior stages of development. The changes and construction of the globe may have been different in different parts; it has not been proved that geological revolutions have been either universal or contemporary. There may have been climates and regions adapted to the existence of the higher class of land animals, while contemporarily therewith other portions of the globe might be undergoing changes beneath the ocean. It is not improbable that the human species dwelt nearly stationary for ages on the old continents of Africa and Asia, while Europe and America were covered with water. Supposing these new continents formed, either by the gradual subsidence of the sea or the rising of its bed, successive inhabitants would follow in the order presented by existing organic remains. While covered by the sea, what now form Europe and America could only be peopled by marine animals; but as the land rose or the waters subsided into their ocean channels, and dry land appeared, reptiles and amphibiæ might become the occupants; next, as the earth became drier and more salubrious, the new continent would be resorted to by terrestrial animals; in a still more advanced stage of purification and salubrity, man himself, as the lord of all the preceding classes of immigrants, would take possession, and as he still continues the living occupant it is premature to look for his petrifaction.

ORIGIN OF THE ANIMATED TRIBES.

Science has mastered many perplexities, but is almost powerless as ever in generation. All that lives, and still more all that moves, must have a pre-existing germ formed independently of the created being, but which is essential to its existence, and fixes the type of organization. The old adage—omne animal ab ovo—may be taken as generally true. But though every animal has its primordial egg or germ, all germs are not identical. In the beginning of life there are other organic elements besides the ovum. Partly on direct proof and partly on good analogy, it may be inferred that these differ in different species—that each in the first stages of existence is bound by a different and immutable mode of development—and, if so, there can be no embryotic identity. "By no change of conditions," says Dr. CLARKE, "can two ova of animals of the same species be developed into different animal species; neither by any provision of identical conditions can two ova of different species be developed into animals of the same kind." If these views be right, and we believe them to be so, there cannot be a transmutation of species under the influence of external circumstances.

Baffled in the effort either to create species or organically to change them, attempts have been made to approach nearer to the source of vitality, and explain the chemical, electric, or mechanical laws by which the vital principle is influenced. For this purpose various hypotheses have been put forth; one is the noted conjecture of Lord MONBODDO, that man is only an advanced development of the chimpanzee or ourang-outang. A second explanation is that given by LAMARCK, who surmised, and with much ingenuity attempted to prove, that one being advanced in the course of generations into another, in consequence merely of the experience of wants calling for the exercise of faculties in a particular direction, by which exercise new developments of organs took place, ending in variations sufficient to constitute new species. In this way the swiftness of the antelope, the claws and teeth of the lion, the trunk of the elephant, the long neck of the giraffe have been produced, it is supposed, by a certain plastic character in the construction of animals, operated upon for a long course of ages by the attempts which these animals make to attain objects which their previous organization did not place within their reach. This is what is meant by the hypothesis of progressive tendencies, and which requires for its validity not only the assumption of a mere capacity for change, but of active principles conducive to improvement and the attainment of higher powers and faculties. More recently ST. HILAIRE has published a paper in which he speaks of the immutability of species as a conviction that is on the decline, and that the age of CUVIER is on the close. Carried away by what Professor PHILLIPS has called a poetical conjecture that cannot be proved, this writer propounded the speculation that the present crocodiles are really the offspring of crocodilian reptiles, the difference being merely the effect of physical conditions, especially operating during long geological periods upon one original race. The human species, he contends, are but an advanced development of the higher order of the monkey tribe, and that the negroes are degenerating towards that type again. According to him the sivatherium—a fossil animal that had been found in the Himalaya mountains—was the primeval type that time had fined down into the giraffe from long-continued feeding on the branches of trees. Dr. FALCONER and Capt. CAUTLEY, however, have shown that anatomical proofs are all against this inference, but if any doubt remained it must yield to the fact, that among the fauna of the Sewalik hills the sivatherium and the giraffe were contemporaries.