86 ARE THE EFFECTS OF USE INHERITED ? 



A/and long-sight certainly tend to be inherited. 1 But 

 we must be careful not to beg the question at issue 

 by assuming that the frequent heredity of short 

 sight necessarily covers the heredity of artificially- 

 produced short-sight. Elsewhere, however, Darwin 

 states more decisively that " there is ground for 

 believing that it may often originate in causes 

 acting on the individual affected, and may thence- 

 forward become transmissible." 2 This impression 

 may arise (i) from the facts of ordinary heredity 

 the ancestral liability being excited in father and 

 son by similar artificial habits, such as reading, and 

 viewing objects closely as among watchmakers and 

 engravers or by constitutional deterioration from 

 indoor life, &c., acting upon a constitutional liability 

 of the eye to the " something like inflammation 

 of the coats, under which they yield " and so 



1 Descent of Man, p. 33. 



2 Variation of Animals and Plants under Domestication, i., 

 453- 



