56 BIOLOGY AND SOCIAL PROBLEMS 



ach's results on the guinea-pigs and rats, the 

 first would probably also profoundly change 

 his character, in that among other things he 

 would lose sexual desire, whereas the second 

 would leave him much the same as he had 

 been except as to this ability to form sperm 

 cells. Thus, depending upon what society 

 wished as a result, one or other course might 

 be adopted. 



Another interesting line of hormone activ- 

 ity of broad, biological significance is that of 

 the relation of the mammalian embryo to the 

 mother. It is well known that as the mamma- 

 lian embryo matures many preparatory changes 

 take place in the maternal body. Prominent 

 among these are the steps taken by the mam- 

 mary glands in preparation for the flow of 

 milk which must be in readiness for the young 

 at birth. How are these preparatory changes 

 initiated ? It is well known that there are no 

 nervous connections between the mother and 

 the embryo, and if the latter influences the 

 former it must be through some such means 

 as hormones. Working upon this suggestion. 

 Starling and Lane-Claypon attempted to as- 

 certain whether in the rabbit the embryos 

 gave out hormones which gradually brought 



