Organic Evolution , Darwinism and the Genesis of Species. i ^ 
the law of heredity thd favorable variation will be trans¬ 
mitted by those possessing it to their offspring and by the 
latter in turn to their progeny. Numerous variations being 
acquired and transmitted, it happens that in the course of 
time certain races will be found to have departed very widely 
from the parent stock, and to have acquired marked char¬ 
acters which thoroughly differentiate them from their con¬ 
geners. 
Thus gradually changes of structure come about and 
lead to the production of those differences which we denom¬ 
inate species, genera, families and orders. Darwin showed 
how man, by careful breeding was able to make a “selection ” 
of any desired character and to perpetuate it. In the same 
way nature “selected” those individuals which were most 
favorably constituted and perpetuated their individualities, 
and this process — to distinguish it from selection by man — 
he called natural selection. 
Darwin’s theory was a very attractive one: it was so 
simple and yet so comprehensive. It seemed to explain 
most satisfactorily what had hitherto been a puzzle to nat¬ 
uralists: the dissimilarity in related species and the simi¬ 
larity in remote species. So adequate did it appear that it 
received a hearty welcome at the hands of naturalists, and 
the book was soon translated into every European language. 
Nevertheless the acceptance of natural selection was not 
universal. Many naturalists like Agassiz, Lyell, the Duke 
of Argyll, and Dawson, rejected it altogether. Others, like 
Mivart, Wiegand. LeConte, Cope, and Hyatt, while accept¬ 
ing the principle of evolution denied the efficacy of nat¬ 
ural selection as the chief factor in development, and en¬ 
deavored to account for the phenomena by various modifi¬ 
cations of Darwin’s theory, or by a rehabilitation, with 
variations, of Lamarck’s discredited transformism. 
That the theory of natural selection by itself is inade¬ 
quate to account for all the phenomena of development was 
practically conceded by Darwin himself in his later works. 
On the lines laid down bv Darwin, natural selection takes 
