HEREDITY. 73 



of that fertilised ovum, and that this is the reason why they 

 are able to develop into offspring like the parent. 



Finally, it may be noticed in connection with heredity, 

 that there is great doubt to what extent the "body" can 

 definitely influence its own reproductive cells. Animals 

 acquire individual bodily peculiarities in the course of their 

 life, as the result of what they do or refrain from doing, or 

 as dints from external forces. The " body " is thus changed, 

 but there is much doubt whether the reproductive cells 

 within the " body " are affected by such changes. Weis- 

 mann denies the transmissibility of any characters except 

 those inherent or congenital in the fertilised egg cell, and 

 therefore denies that the influences of function and environ- 

 ment are, or have been, of any importance in the evolution 

 of many celled animals. Such influences affect the body, 

 but do not reach its reproductive cells, and are therefore 

 non-transmissible. Many of the most authoritative biolo- 

 gists are at present of this opinion. On the other hand, 

 many still maintain that profound changes due to function 

 or environment may saturate through the organism, and affect 

 the reproductive cells, and thus the race. The whole 

 question remains under discussion. 



