40 Dynamic Evolution 



sexual characters requires us to keep that 

 point in mind and not to place factors in 

 equations where they do not belong. As it is 

 energy which causes characters to grow, we 

 may argue that the energy which causes the 

 beard to grow on the face of a man must be, 

 in some way, different from the energy which 

 fails to cause it to grow on the face of a 

 woman. Hence, those things which we call 

 secondary sexual characters are simply pro- 

 ducts of an energy which has a sexual rela- 

 tionship, and it is the energy and not the 

 observed character which is (secondary) 

 sexual. 



Arresting sexual development by castration 

 is known to arrest the development of second- 

 ary sexual characters. The eunuch develops 

 neither a beard nor a bass voice. In trotting 

 horses, castration is largely practiced, and 

 geldings form a large part of standard per- 

 formers. In examining trotters it is there- 

 fore necessary to divide them into three 

 groups, — stallions, mares, and geldings. As 

 pointed out before, age of animals is time, 



