854 The American Naturalist. [October, 
I cannot but wish that one of his numerous disciples could 
have been chosen for this task. But I must not pass it by, for it 
is the most characteristic feature of Cope’s work and the one 
he most esteemed. 
Cope began his public scientific career, it will be remem- 
bered, in the same year in which Darwin’s long studies had 
fructified into his “ Origin of Species.” 
As was quite natural with his keen instincts, Cope early 
adopted the doctrine of transmutation of species and recognized 
the truth that all the animals of the present epoch are de- 
scendents from those of past times with modifications which 
separate them as species, and eventually as representatives of 
genera, of families and orders differing from the earlier ones 
as we retrace the the steps of Time farther and farther back. 
He was not, however, satisfied with Darwin’s theory, and de- 
nied that natural selection was a sufficient factor for differen- 
tiation. He would not admit that animals were passive sub- 
jects and that the slight variations which were manifested in 
the progeny of species were sufficient to enable Nature to select 
from and to fit for future conditions. He contended that the 
volition and endeavors of an animal had much to do with 
- future progeny as well as its own brief life. In short, he 
claimed that characters acquired by animals through their 
own efforts or forced on them by various external agencies or 
accidents might be transmitted to their offspring. He further, 
first in a chapter in his “ Synopsis of the Cyprinide of Penn- 
sylvania,” outlined, and later, in “ The Origin of Genera,” he 
elaborated, a peculiar theory characterized mainly by what he 
called (with Professor Hyatt) “the law of acceleration and re- 
tardation” in development. Darwin complained that he could 
never understand this law, and Cope complained that Darwin 
had not stated his views correctly in an attempted abstract. I 
therefore give Cope’s views, restated in his own language, 
summarizing them years afterwards. “The following doc- 
trines,” he says, were taught: ” 
First, that the development of new characters has been accomplished 
by an acceleration or retardation in the growth of the parts changed. This 
was demonstrated by reference to a class of facts, some of which were new, - 
which gave ground for the establishment of the new doctrine. 
