TJie InJieritance of Acquired Characters 13 



cism in regard to such inheritance, but it was Weis- 

 MANN (17) who was most intluential in combating 

 the idea. After Weismann's presentation of the sit- 

 uation, biologists were divided into two camps in 

 reference to the question: (i) neo-Lamarckians, who 

 affirmed behef in inheritance of acquired characters, 

 and (2) neo-Darwinians, who denied it. Until very 

 recently, at least, the bulk of the evidence of genetics 

 has served to refute inheritance of acquired charac- 

 ters. 



Much of the lack of agreement in this controversy 

 is due to the dehnition of an acquired character. It 

 should be kept in mind that actual characters are not 

 inherited, but only the determiners, which regulate the 

 way in which the organism reacts to its enviromncnt. 

 For example, when it is said that a child inherits its 

 father's nose, the statement is not meant to be literally 

 true; it is meant that just as there was something in the 

 body of the father that was responsible for the develop- 

 ment of a particular type of nose, so there was a similar 

 something in the child's body that developed a similar 

 result. It is merely a matter of convenience to speak 

 of the inheritance of characters. 



Weismann defined an acquired character as ''any 

 somatic modification that does not have its origin in the 

 germ plasm." This definition is not always easy to 

 apply. Examples of acquired characters in the Weis- 

 mann sense are mutilations, results of function (as in 

 the use or disuse of certain organs), many diseases that 

 affect the bodily mechanism, and, to use a rather vague 

 expression, effects of environment. Weismann gave 

 three reasons for rejecting the belief in inheritance of 



