82 HEREDITY. 
two categories. Either they are inborn or they are ac- 
quired. An inborn or innate character is one which, in 
common parlance, arises in the individual ‘by nature.’ 
Thus arms, legs, eyes, ears, head, etc., are all inborn char- 
acters. The child inherits them from his parent. But, 
if during its development, or after the completion of the 
development any one of the inborn characters of an 
individual is modified by some occurrence, the change 
thus produced is known as an acquired character, or, 
shortly, as an acquirement. 
“Thus all the effects of exercise are acquirements ; 
for example the enlargement which exercise causes in 
muscles. The effects of lack of exercise are also ac- 
quirements; for example, the wasting of a disused 
muscle. 
“The effects of injury are acquirements ; for example, 
the changes in a diseased lung or injured arm. Every 
modification of the mind is also an acquirement; for ex- 
ample, everything stored within the memory. 
“If a man be blinded by accident or disease, his 
blindness is acquired. But if he comes into the world 
blind, if he be blind by nature, his blindness is inborn. 
If a son be naturally smaller than his father, then his in- 
feriority of size is inborn; but if his growth be stunted 
by ill health or lack of nourishment or exercise, his in- 
feriority is acquired. 
“Lamarck held, as people in all ages have held, that 
characters acquired by parents are also transmissible to 
some extent, and that evolution results from their ac- 
centuation during succeeding generations. Lamarck’s 
theory is rejected totally by the modern followers of Dar- 
win. 
“Ten thousand men might break their fingers, yet 
among their offspring not one might have a crooked 
finger. Consider on the other hand for how many gen- 
