1894.] Neo-Lamarckism and .Neo- Darwinism. 675 
the fact is so well known, that it seems almost useless to refer 
to it here; and yet there are some phases of it upon which I 
cannot forbear to touch. 
Weismann declares that he uses the term “ acquired charac- 
ter” in its original sense. This term, or at least the idea, was 
first employed, as we have seen, by Lamarck, who used it or 
an equivalent phrase to designate “every change acquired in 
an organ by a habitual exercise sufficient to have brought it 
about.” In fact, the basis of Lamarck’s philosophy is the as- 
sumption of the hereditability of characters arising directly 
from use or disuse; and his idea of an acquired character is, 
therefore, one which appears in the lifetime of the individual 
from some externally inciting cause. Darwin’s notion, while 
less clearly defined, was essentially the same, and he collected 
a mass of evidence to show that such characters are transmis- 
sible; and he even went farther than Lamarck, and attempted 
to show that mutilations may be hereditary. Weismann’s 
early definition of acquired characters is plain enough. Such 
characters, that is, the somatogenic, “not only include.the 
effects of mutilation, but the changes which follow from in- 
creased or diminished performance of function, and those 
" which are directly due to nutrition and any of the other exter- 
nal influences which act upon the body.” Standing fairly and 
squarely upon this definition, it is easy enough to’ disprove it 
—that is, to show that some characters thus aequired are her- 
editary. But the moment proofs are advanced, the definition 
is contracted, and the Neo-Darwinians declare that the given 
character was potentially present in the germ and was not 
primarily superinduced by the external conditions—a position 
which, while it allows of no proof, can neither be overthrown. 
‘A cow lost her left horn by suppuration, and two of her calves 
had rudimentary left horns; but Weismann immediately says, 
“The loss of a cow’s horn may have arisen from a congenital 
malformation.” Certainly! and it may not; and the presump- 
tion is that it did not. A soldier loses his left eye by inflam- - 
mation, and two of his sons have defective left eyes. Now, 
“the soldier,” says Weismann, “did not lose his left eye be- RC D 
cause it was injured, but because it was predisposed to become. Le 
^ 
