( 14 ) 
balance established between environment and innate qualities 
resulting in the production of a normal individual) to produce 
an appreciable change, such a modification or ‘ difference’ 
may be called an acquired character.” * 
Such results of abnormal conditions undoubtedly supply 
extremely striking examples of acquired characters, but it is, I 
submit, a mistake to make too much of abnormality, or to 
import it into a definition. Some of the most marked and 
certainly the most easily studied and tested of acquired char- 
acters are the differences between the effects of alternative 
environments, all of which are normal, upon the individuals of 
a single species. The green colour of a larva of Amphidasys 
betulavia, if fed upon broom, is an acquired character, as is the 
dark colour it would assume wpon oak, ete. I think there- 
fore that a more satisfactory definition of at any rate a large 
class of acquired characters may be framed as follows :— 
“Whenever change in the environment regularly produces 
appreciable change in an organism, such difference may be 
called an acquired character.” 
Sir Edward Fry has objected to Mr. Galton’s definition ,—and 
his objection would equally apply to that which I have sug- 
gested above—that “the possibility of inheritance is excluded 
by the definition, and the inquiry whether acquired characters 
are inherited is impossible.” 7 
This appears to me to be only a verbal difficulty. Before 
attempting to prove whether a certain class of characters can 
be inherited, it is essential to be able to decide whether a given 
character which it is proposed to test belongs to the class. 
If a satisfactory criterion can be reached we can proceed with 
the test even though the name “acquired” be by our defini- 
tion denied to the character after transmission by inheritance. 
The interest of the result would remain all the same. If the 
character were there—appreciable, measurable,—the effects 
would be incalculable in their importance, and would not be 
diminished one iota by the consideration that the name would 
no longer apply. Sir Edward Fry’s criticism does indeed 
* PBaldwin’s ‘‘ Dictionary of Philosophy and Psychology,” p. 10. 
+ “Nature,” vol. li, 1894, p. 198. See also Professor Lankester’s 
reply to the criticism, on p. 245, 
