CHAPTER 
III. 
THE TRANSMUTATION OF SPECIES. 
“ Corpora vertuntur nec quod fuimusve sumusve 
Cras erimus.” —Ovid. 
We now propose to ask what part the theory of Natural 
Selection plays in connection with other possible methods 
of the transmutation of species. 
It may be well, for the sake of clearness, to look at this 
matter (first) from the point of view of those who believe 
that Natural Selection is the sole method by which the 
transmutation of species is brought about, and (secondly) 
from the point of view of those who believe that trans 
mutation can take place apart from Natural Selection as 
well as through its agency. In the former case, the prin 
ciple is laid down that no modification acquired by “ the 
body” of the individual during life can be inherited ; that 
only those variations with which an individual is born 
can be inherited by the offspring ; and that the favour 
able variations can only survive through the action of 
Natural Selection—through selection by life and death. 
We must continually bear in mind the reason why 
the principle of selection is esteemed so important in this 
connection. Those variations which are necessarily and 
inevitably associated with sexual reproduction would be 
swallowed up in the average of the race by the principle 
of regression to mediocrity, unless similar variants were 
compelled to breed together. But this principle of selec 
tion is only required in the case of those variations which