34 INTERNAL SECRETIONS 



observations on the psycho-sexual behaviour of the castrated 

 mammal were made by Steinach (1894; see also Exner, 1903, 

 p. 221). He records that male rats castrated at an age of 45 

 days first showed signs of sexual activity at the ninetieth 

 day, i.e., at the same time as a normal control animal. They 

 recognised a female "on heat," followed her in the same 

 manner as a normal male would, and even made some attempts 

 at coitus. But erection was only rarely to be observed. With 

 a normal strange male the "castrates" fought less vigorousl3\ 

 After a space of a year even these traces of a diminished sexual 

 activity disappeared. 



I have made some observations, but not very systematically, 

 on prepuberally castrated guinea pigs. If a female is put 

 into a cage with a normal male, the latter recognises her b\^ 

 smelling her body in the neighbourhood of the vulva ; a similar 

 behaviour on the part of the normal male may be observed 

 even when the other animal is also a male. If the strange 

 animal is recognised as a female, she will be followed by the 

 male, who makes attempts at coitus. The normal male 

 shows great tenacity in following the female guinea pig and 

 making these attempts. The prepuberally castrated male, 

 on the other hand, shows no such tendency. Sometimes 

 the "castrate" will fight with the female, but often he 

 \vill display no excitement whatever. I once witnessed the 

 following scene. A female, probably on heat, was followed 

 by a normal male with great tenacity. When the normal 

 male was taken away, and replaced by a castrated male, the 

 latter remained quietly in a corner. The female approached 

 him, and even bit his fur, but without any result ; the 

 "castrate" remained as quiet as before. A "castrate," if 

 put with a female together with a normal male, will be recog- 

 nised sooner or later by his want of sexual interest. If attempts 

 are made by the castrated male to follow the female, the normal 

 male will interfere, and the "castrate" will soon become 

 quiet. He will only fight if attacked. Nevertheless, castrated 

 animals sometimes fight together in the presence of a female. 



There can be no doubt that postpuberally castrated males 

 may show sexual behaviour for a considerable time. Steinach 

 records normal sexual libido in rats four, or even six, months 

 after csLStrsition; IJchtenstern (1916a) confirmed these observa- 

 tions. Faure in our Institute observed sexual activity in 



