HEREDITY AND EVOLUTION 115 



upon mind, than occurs in action of the mature 

 organism on the unfolding germ-cell. In its 

 beginnings, it seems as if the life of the germ-cell 

 were in some ways more independent of the parent 

 life, than the mind-life of the child can be. 



Seeking, in harmony with these conclusions, such 

 evidence as may be available in support of heredity in 

 mental history, the utmost that can be done here 

 seems to be classification of mental phenomena, such 

 as may guide to inference. There is a large mass 

 of facts to be so classified. Deeper consideration of 

 these seems required in order to come to some fuller 

 interpretation of man s place in Nature. 



Of these facts, the main body belongs to the border 

 land, where relations physical and mental come 

 together under notice. These appear in a variety of 

 aspects, but the relations of the two sides of our 

 nature are certain. Heed must be given, however, to 

 the two modes of knowing, as well as to the dualism 

 appearing in the single life. We may, therefore, have 

 to contemplate facts, first from the physical side, 

 afterwards from the mental side. 



All our relations to external Nature supply points 

 at which variations in physical life, hereditarily trans 

 mitted, have a bearing on mind-life. Variations in 

 general susceptibility of the nerve system, and in 

 structure of the organs of special sense, involve 

 specialities affecting the whole individual life. Here we 

 include also the facts belonging to the tangled history 

 of hereditary disease, and special variations in nerve 

 and brain, depressing or exciting. These differences 

 lie strictly within the lines of physical inheritance, yet 

 they deeply affect personal experience, and must have 



