THE REPRODUCTIVE ORGANS 69 



tus. The vesiculse seminales and the prostate are small and 

 atrophied. The penis does not share in the atrophy, so that 

 in Eastern countries it is frequently considered necessary to 

 remove this as well as the testes. The atrophy of the vesiculse 

 seminales and the prostate after castration can also be noted 

 experimentally in animals ; and, further, if castration be 

 performed in quite young animals, the operation prevents the 

 development of the prostate, whereas division of the vas and 

 the abolition of the production of semen have no arresting 

 influence. The atrophy of the prostate after castration led 

 to the introduction of this operation as a method of treating 

 prostatic enlargement. Castration on one side produces no 

 effect, the retention of a single testis being sufficient to main- 

 tain the functional integrity of the prostate. It is stated, 

 also, that Cowper's glands atrophy after castration. It is 

 generally assumed that the growth and integrity of the prostate 

 are determined by a hormone furnished by the testis. On this 

 hypothesis we might explain hypertrophy of the prostate as 

 due to a hypersecretion of the hormone. This would not be 

 inconceivable if we make the further hypothesis that the 

 internal secretion proceeds from the interstitial cells of the 

 testis, and these might still be active, or even of increased 

 activity at a time when the seminiferous tubules are in process 

 of degeneration. 



So much for the influence exerted by the testis, in all proba- 

 bility by means of an internal secretion, upon the growth and 

 development of the other generative organs. We have now to 

 consider the influence of the testis in developing and main- 

 taining the secondary sexual characters. It is, perhaps, well 

 to point out that castration never induces a condition in any/ 

 respects resembling the female type ; the condition is infantile, 

 and not female. The effects in man are well known, and have 

 already been briefly referred to. The relation between testis 

 and secondary sexual characters is, however, closer in those 

 animals in which we find increased testicular activity in the 

 breeding season associated with a periodic development of other 

 sexual characters. An example is given by Marshall. In the 

 male elephant the glands on the side of the face emit a musky 

 secretion during rut. 



If the testes are extirpated from quite young stags, the 

 antlers never develop ; if the operation is performed at the 



