166 DARWINISM AND HUMAN LIFE 



which may have disturbed the normal routine of 

 reproduction. 



LOGICAL POSITION OF THE QUESTION. Let us 

 notice the logical position of the question. There 

 are two possible lines of argument : (a) by experi- 

 ment, and (6) by interpretation, (a) As to ex- 

 periment, it is plain that hundreds of failures 

 to prove the transmission do not demonstrate 

 its impossibility. They only show that it is 

 not usual. One good case experimentally proved 

 would show that the transmission is possible. 

 The best case we know is Kammerer's, and it 

 does not seem cogent. Perhaps better cases will 

 become known. The Lamarckian does not, of 

 course, say that every change of conditions will 

 produce appreciable hereditary effects in a few 

 generations, or that any particular change of 

 conditions chosen more or less arbitrarily for 

 experimental purposes will produce recognisable 

 results in the following generation. But do we 

 know of any clear case of even a faint trace of a 

 well-defined structural modification being trans- 

 mitted ? (b) As to the second method, that of 

 the interpretation of facts, it cannot be conclusive 

 either, since each side has to prove a negative in 

 order to establish its case. The Neo-Lamarckians 

 have to show that the phenomena they adduce 

 as illustrations of modification-inheritance cannot 

 be interpreted as the results of selection operating 

 on germinal variations. In order to do this to 

 the satisfaction of the other side, the Neo-Lamarck- 

 ians must prove that the characters in question 

 are outside the scope of natural selection, that 

 they are non-utilitarian and not correlated with 

 any useful characters a manifestly difficult task, 



