THE LAMARCKIAN THEORY 417 



should have some weight as scientific deductions. We can learn 

 very little therefore from th(^ controversial matc^-ial now available. 

 One side presents as imi:)osing authority as the other; the scientists 

 are by no means united against the inheritance of acquired char- 

 acters, nor are its supporters lacking in scientific training and 

 ability. 



Since ancient times many men have accepted the idea in con- 

 nection with human evolution without any critical attempt to 

 establish its validity. The close association of human progress 

 with the activities of past generations is sufficient to justify this 

 feeling, but far from sufficient as yet to prove that any change 

 has actually been produced in the heredity of the human race 

 as a result of human activities. If we could know that education 

 gradually modifies the human mind, it would be of the greatest 

 value to us. This is, however, merely supposed to occur by those 

 who favor the Lamarckian point of view. The only thing definitely 

 known to us in this connection is that human experience is per- 

 petuated through records and teaching, so that future generations 

 may profit by it as a part of their environment, even though they 

 may have received no inheritance from it. 



Herbert Spencer stands out among those who have believed in 

 the inheritance of acquired characters, and like others, his attitude 

 was an outcome of such keen appreciation of the intimate relation- 

 ship existing between an organism and its environment that he 

 could not imagine an evolutionary process in which environment 

 was wholly passive. 



Circumstantial Evidence. Much evidence has been brought 

 to the support of this point of view from the study of existing 

 animals. The similarity of such things as heritable callosities 

 and the callosities which appear in individuals as acquired charac- 

 ters in response to friction is one such case. It has been regarded 

 as wholly logical to conclude that inherent callosities located where 

 they resist extreme friction may well be the result of the long- 

 continued action of such a stimulus. However convincing one 

 may find this type of evidence, he must admit that it is not proof 

 that the character in question was so developed. In the one case 

 we deal with a definitely germinal character in the usual sense; 

 in the other we deal with a character which appears anew with 

 every generation only when the proper environmental stimulus 

 favors its development. 



