XIV 
FUNDAMENTAL PROBLEMS 
443 
Concluding Remarks. 
Having now passed in review the more important of the 
recent objections to, or criticisms of, the theory of natural 
selection, we have arrived at the conclusion that in no one 
case have the writers in question been able materially to 
diminish its importance, or to show that any of the laws or 
forces to which they appeal can act otherwise than in strict 
subordination to it. The direct action of the environment as 
set forth by Mr. Herbert Spencer, I)r. Cope, and Dr. Karl 
Semper, even if we admit that its effects on the individual 
are transmitted by inheritance, are so small in comparison 
with the amount of spontaneous variation of every part of 
the organism that they must be quite overshadowed by the 
latter. And if such direct action may, in some cases, have 
initiated certain organs or outgrowths, these must from their 
very first beginnings have been subject to variation and 
natural selection, and their further development have been 
almost wholly due to these ever-present and powerful causes. 
Francis Galton’s Theory of Heredity (already referred to at p. 417) which 
was published thirteen years ago as an alternative for Darwin’s theory of 
pangenesis. 
Mr. Galton’s theory, although it attracted little attention, appears to me 
to be substantially the same as that of Professor Weismann. Galton’s 
“ stirp ” is Weismann’s “germ-plasm.” Galton supposes the sexual elements 
in the offspring to be directly formed from the residue of the stirp not used 
up in the development of the body of the parent — Weismann’s “ continuity 
of the germ-plasm.” Galton also draws many of the same conclusions from 
his theory. He maintains that characters acquired by the individual as the 
result of external influences cannot be inherited, unless such influences act 
directly on the reproductive elements — instancing the possible heredity of 
alcoholism, because the alcohol permeates the tissues and may reach the 
sexual elements. He discusses the supposed heredity of effects produced by 
use or disuse, and explains them much in the same manner as does Weismann. 
Galton is an anthropologist, and applies the theory, mainly, to explain the 
peculiarities of hereditary transmission in man, many of which peculiarities 
he discusses and elucidates. Weismann is a biologist, and is mostly concerned 
with the application of the theory to explain variation and instinct, and to 
the further development of the theory of evolution. He has worked it out 
more thoroughly, and has adduced embryological evidence in its support; but 
the views of both writers are substantially the same, and their theories were 
arrived at quite independently. The names of Galton and Weismann should 
therefore be associated as discoverers of what may be considered (if finally 
established) the most important contribution to the evolution theory since the 
appearance of the Origin of Species. 
