298 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, ete. 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 philosophie 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, mean- 
ing 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 paleo- 
zoologist 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 extinc- 
tion, for the paleontologist alone is immortal. 
PALEONTOLOGY AND THE RECAPITULATION THEORY 
By BE. R. CUMINGS 
INDIANA UNIVERSITY 
i 
ATHER 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. 
