

74 GENETICS 



somatic characters to the germ-cells has not been dis- 

 covered, is not proof that such a mechanism does net 

 exist. It may simply be beyond our present powers of 

 penetration. 



B. EVIDENCE FOR TRANSMISSION OF ACQUIRED 

 CHARACTERS INCONCLUSIVE 



The evidence for the inheritance of acquired charac- 

 ters was, for a long time, taken for granted. This 

 theory was the most obvious explanation of many facts 

 and so was accepted without question. An obvious 

 interpretation, however, is not always the correct one. 

 The sun appears to go around the earth, but astrono- 

 mers assure us that it does not. 



When Weismann began to sift the evidence for the 

 inheritance of acquired characters, he found that it 

 was largely based upon opinion rather than fact, much 

 like the popular belief with regard to the causation of 

 warts by handling toads. 



The supposed evidence for the inheritance of ac- 

 quired characters falls chiefly into the following cate- 

 gories : 



a. Mutilations; 



b. Environmental effects ; . 



c. The effects of use or disuse; . 



d. The transmission of disease ; 



e. Immunity; 



f. Prenatal influences. 





