174 HEREDITY 



form one child and those which unite to form another, 

 but there are very important dynamic differences, and 

 it is only when the subject is approached from this 

 point of view that the various problems connected 

 with it can be treated with any hope of success. 

 The deter- Hereditary transmission, as applied to this or that 

 of sex. part, probably depends on the conductivity of the 

 parental nervous system and on the force of the 

 nutritive or metabolic impulses, and in this way one 

 must suppose that the sex of the offspring is 

 determined. There are, however, many secondary 

 factors in prepotency which are both variable and 

 difficult to ascertain. Under these circumstances it is 

 manifestly absurd to pretend, as some do, that a child 

 always inherits certain traits or characteristics from 

 its mother and others from its father. The utmost 

 that can be said is that women are more sensitive, 

 as a rule, than men. Greater sensibility may be 

 regarded as equivalent to greater conductivity, but 

 not to greater transmitting power. As already said, 

 there are other factors to consider, and any generaliza- 

 tion beyond this, from whatever quarter it may come, 

 should be received like an old woman's tale. 



The moral aspect of heredity may be expressed in a 

 very few words. When any form of nervous vibration 

 attains a high degree of intensity there is consider- 

 able likelihood of its being transmitted from parent to 

 child. When thus transmitted, unless counteracted, 

 it will often manifest itself in a still more pronounced 

 manner ; so that acts which in one generation may 



