THE GOSPEL OF SCIENCE 5 



devoted themselves chiefly to the consideration 

 of the question of heredity, viewed, as might be 

 expected, from the Mendelian standpoint. 



Now, at this point it may be said that there are 

 at least two things which we should like to know 

 about heredity the vehicle and the laws. It is 

 clear that we might know something, perhaps 

 even a good deal, about one of these without 

 knowing anything about the other. 



Such in fact is the case ; for we know, it may 

 fairly be said, nothing about the vehicle. There 

 are two very widely distinct opinions on this 

 point. There is the mnemic theory, recently 

 brought before us by the republication of Butler's 

 most interesting and suggestive work with its 

 translations of Bering's original paper and Von 

 Hartmann's discourse and its very illuminating 

 introduction by Professor Hartog. 1 



And there is the continuity theory which 

 teaches that in some way or another the character- 

 istics of the parents and other ancestors are 

 physical parts of the germ. An attempt to ex- 

 plain this was made by Darwin in his theory of 

 Pangenesis. Others have essayed what Yves 

 Delage calls " micromeristic " interpretations. 

 As to all of these it may be said that when they 

 are reduced to figures the explanation becomes 

 of so complex a character as utterly to break down. 

 We shall see that Professor Bateson adopts a third 

 very nebulous explanation. But as regards the 

 laws of heredity there is something else to be 

 said ; for here we really do know something, and 

 1 Unconscious Memory. Fifield. 1910. 



