It is well said that all organic beings have been formed on two great laws; Unity of type, and Adaptation to the conditions of existence.... Mr. Darwin harmonizes and explains them naturally. Adaptation to the conditions of existence is the result of Natural Selection; Unity of type, of unity of descent.”
Gray’s article was soon followed by another one from Agassiz on Individuality and Specific Differences among Acalephs, but the running title is “Prof. Agassiz on the Origin of Species” (30, 142, 1860). Agassiz stoutly maintains his well known views, and concludes as follows:
“Were the transmutation theory true, the geological record should exhibit an uninterrupted succession of types blending gradually into one another. The fact is that throughout all geological times each period is characterized by definite specific types, belonging to definite genera, and these to definite families, referable to definite orders, constituting definite classes and definite branches, built upon definite plans. Until the facts of Nature are shown to have been mistaken by those who have collected them, and that they have a different meaning from that now generally assigned to them, I shall therefore consider the transmutation theory as a scientific mistake, untrue in its facts, unscientific in its method, and mischievous in its tendency.”
Dana, in reviewing Huxley’s well known book, Man’s Place in Nature (35, 451, 1863), holds that man is apart from brute nature because man exhibits “extreme cephalization” in that he has arms that no longer are used in locomotion but go rather with the head, and because he has a far higher mentality and speech. As for the Darwinian theory, the evidence, he says, “comes from lower departments of life, and is acknowledged by its advocates to be exceedingly scanty and imperfect.”
The growth of evolution is set forth in the Journal in Asa Gray’s article on Charles Darwin (24, 453, 1882), which speaks of the latter as “the most celebrated man of science of the nineteenth century,” and, in addition, as “one of the most kindly and charming, unaffected, simple-hearted, and lovable of men.” In regard to the rise of evolution in America, more can be had from Dana’s paper on Asa Gray (35, 181, 1888). Here we read, as a sequel to his Thoughts on Species, that the “paper may be taken, perhaps, as a culmination of the past, just as the new future was to make its appearance.” Finally, in this connection there should be mentioned O. C. Marsh’s paper on Thomas Henry Huxley (50, 177, 1895), wherein is recorded the latter’s share in the upbuilding of the evolutionary theory.
We have seen that originally Dana was a creationist, but in the course of his long and fruitful life he gradually became an evolutionist, and rather a Neo-Lamarckian than a Darwinian. This change may be traced in the various editions of his Manual of Geology, and in the last edition of 1895 he says his “speculative conclusions” of 1852 in regard to the origin of species are not in “accord with the author’s present judgment.” “The evidence in favor of evolution by variation is now regarded as essentially complete.” On the other hand, while man is “unquestionably” closely related in structure to the man-apes, yet he is not linked to them but stands apart, through “the intervention of a Power above Nature.... Believing that Nature exists through the will and ever-acting power of the Divine Being, and ... that the whole Universe is not merely dependent on, but actually is, the Will of one Supreme Intelligence, Nature, with Man as its culminant species, is no longer a mystery.”
In America most of the paleontologists are Neo-Lamarckian, a school that was developed independently by E. D. Cope (1840–1897) through the vertebrate evidence, and by Alpheus Hyatt (1838–1902) mainly on the evidence of the ammonites. They hold that variations and acquired characters arise through the effects of the environment, the mechanics of the organism resulting from the use and disuse of organs, etc. One of the leading exponents of this school is A. S. Packard, whose book on Lamarck, His Life and Work, 1901, fully explains the doctrines of the Neo-Lamarckians.
The Growth of Invertebrate Paleontology.
How and by whom paleontology has been developed has been fully stated in the Journal in a very clear manner by Professor Marsh in his memorable presidential address of 1879, History and Methods of Palæontological Discovery (18, 323, 1879), and by Karl von Zittel in his most interesting book, History of Geology and Palæontology, 1901. In this discussion we shall largely follow Marsh.
The science of paleontology has passed through four periods, the first of them the long Mystic period extending up to the beginning of the seventeenth century, when the idea that fossils were once living things was only rarely perceived. The second period was the Diluvial period of the eighteenth century, when nearly everyone regarded the fossils as remains of the Noachian deluge. With the beginnings of the nineteenth century there arose in western Europe the knowledge that fossils are the “medals of creation” and that they have a chronogenetic significance; also that life had been periodically destroyed through world-wide convulsions in nature. From about 1800 to 1860 was the time of the creationists and catastrophists, which may be known as the Catastrophic period. The fourth period began in 1860 with Darwin’s Origin of Species. Since that time the theory of evolution has pervaded all work in paleontology, and accordingly this time may be known as the Evolutionary period.