20 



INTERNAL SECRETIONS 



part of the penis. Wholly different is the copulatory apparatus 

 of a full grown ^'castrate" {Fig. 9). The vesiculae and the 

 prostate are here in the same stage of development as in a four 

 or five weeks old animal, and the penis has grown but little. I 

 observed an underdevelopment of the genital apparatus also in 

 white mice which were castrated by Ottow and myself, when 

 weighing about 4.5 gr. We observed a very marked under- 

 development of the vesiculae and of the penis. 



Fig. 9.^ — Male rat, 8 months old, castrated at the age oj i 

 month. Yd. = sectioned vasa deferentia. Prostate and 

 seminal vesicles remain at the same infantile stage as 



I made detailed observations on guinea pigs. The penis of 

 an adult guinea pig, castrated when about two weeks old, is 

 smaller than in the normal animal, but externally it has the 

 characteristic features of the normal penis (Fig. 10). We see 

 that the distal part of the corpora cavernosa penis, not yet 

 formed at the time of prepuberal castration, can develop 

 however to a certain degree (Fig. 10, D and E). This is 

 of great interest, as the development of this part of the penis 



