Page:Popular Science Monthly Volume 77.djvu/304

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THE POPULAR SCIENCE MONTHLY

The paleontologist, more than any other naturalist, is concerned with the product of these interactions, and to him, oftener than to others, has come the question, Are these results species? and, if so, what are the criteria for the separation of species? The student of hard structures appreciates the difficulty of drawing sharp lines, and one of his most trying tasks is to satisfy the idiosyncrasies of his colleagues in the making of species, subspecies, varieties, etc. The student of hard parts finds transitional forms the rule, and he dare not grind them to powder under his heel with the remark credited to Stimpson, that "that is the proper way to dispose of those damned transitional forms."

The philosophic paleontologist recognizes more readily than any one else the truth of the dictum that nature knows only individuals, and that species are special creations, called into being by the fiat of the naturalist. He is concerned not so much with the origin of species as with the origin of individuals; and while he makes use of the artificial divisions called species, and sometimes finds his chief joy in multiplying and subdividing them, he still recognizes their non-existence, and turns to individuals. He may, perhaps, prefer to speak of mutations, meaning individuals, nevertheless.

But individuals are complex entities, and the paleontologist can not investigate their genesis before he has thoroughly investigated the origin of the parts composing it. As Professor Osborn has said, the paleozoologist is concerned primarily with the origin of structures. He alone is able to trace their development, for he is present at their birth, he follows their whole history, and will be present also at their extinction, for the paleontologist alone is immortal.


PALEONTOLOGY AND THE RECAPITULATION THEORY

By E. R. CUMINGS

INDIANA UNIVERSITY

I

BATHER once said that "If the embryologists had not forestalled them, the paleontologists would have had to invent the theory of recapitulation." This may be considered as a fair sample of the attitude of at least the Hyatt school of paleontologists toward the theory. It is doubtful if any paleontologist could be found who wholly rejects it. In violent contrast with the more or less complete acceptance of the theory by paleontologists, is the attitude of many embryologists and zoologists. Montgomery and Hurst have perhaps put the case against recapitulation more strongly than any one else. The former says, for example,

The method is wrong in principle, to compare an adult stage of one organism with an immature stage of another.