ORIGINAL COMMUNICATIONS. 
The Influence of the Nervous System in Organic 
Evolution. 
By R. F. Licorisy, M.D. 
THE majority of biologists may be at present divided into two schools, 
Neo-Darwinian and Neo-Lamarckian, and besides these there are others 
who still profess to be unable to reconcile themselves to the truths of 
organic evolution as interpreted by either party, and who find a pro- 
minent representative in the celebrated pathologist Virchow. In 
addition to the above there are a few who, like the writer, are pure 
Lamarckians, and who, accepting the data of Lamarck, interpret them 
by the hight of present day knowledge, and look on “natural selection ” 
and “survival of the fittest ” as mere “ figures of speech,” expressive of 
results which have been brought about by functional and environmental 
adaptation. Of the two leading schools the more numerous is 
undoubtedly that of the Neo-Darwinians, who see in natural selection 
an all-sufficient cause for organic evolution. The members of the 
other school, that of the Neo-Lamarckians, consider natural selection 
as merely one of the factors of organic evolution, another being the 
inheritance of the results of the organism’s post-natal experiences. 
Let us look more closely at these theories to see if we cannot find 
therein such a relationship or analogy as would lead us to believe that 
a sheght modification in the basis of one or the other or both will tend 
to more harmony than at first sight would appear to be possible. For 
it must be remembered that both schools are represented by able and 
gifted men who devote themselves to experiment and observation, and 
are all equally eager to arrive at truth. 
Taking the Neo-Darwinians first, we find the basis of their theory 
to be this. Organic evolution depends on, and is carried out through, 
the variations which appear at the conclusion of the ontogenetic 
development, 2.c. at birth. This is the basis of their theory of organic 
evolution. To the question, What gives rise to those variations? we 
have as answers:—(1) Cause unknown (Darwin); (2) Chance—a 
17—wnar, sc.—vou. xv. No. 92. 253 
