172 HEREDITY 



improbable that the mental impression alone would 

 suffice in all cases to account for the results actually 

 obtained. Others, like Professor James Law, have 

 suggested that the impregnated ovum impresses its 

 own character on the mass of the decidua, and 

 through this on the maternal placenta, and that this 

 in turn impresses its character on the decidua and 

 embryo of the next succeeding generation. The 

 objection to this, a partial one, is that the decidua 

 itself is renewable. We must therefore go further 

 than the last observer, and search for some other sort 

 of tissue in which the dynamic impulses embodied in 

 the spermatozoa and in the foetus can be stored up in 

 the system until they are again rendered active. 

 Can this tissue be any other than the nervous 

 system? Do we not know, as well as we know 

 anything in physiology, that the nervous system is a 

 great storehouse of impressions or impulses? Does 

 not the womb and all its contents constitute a most 

 notable portion of the environment of the nervous 

 system, a portion the more remarkable because of the 

 intensified activity which is common to both during 

 the period of gestation ? Does not the nature of the 

 metabolism, going on in any part of the body, 

 influence the nervous system often as a whole? If 

 in this case there is no direct nervous connection 

 between the foetus and the nervous system of the 

 mother, are we to deny that impulses or dynamic 

 impressions may reach the latter through the medium 

 of the ether, which permeates the womb as it does 



