THE MALE ORGANS 349 



The prostate consists of alveoli lined with cubical 

 epithelium and separated by connective tissue and plain 

 muscular fibres. The secretion of the prostate probably 

 serves to dilute the semen, to prolong the activity of the 

 spermatozoa by affording them nourishment and to 

 wash out traces of urine from the urethra preparatory 

 to ejaculation. 



Concerning the function of Cowper's glands, which open 

 into the urethra about two inches below the prostate, httle 

 is known. From the fact that their secretion pjpcedes 

 ejaculation it is suggested that they, like the prostate, serve 

 to clean the urethra of urine. 



The Internal Secretion of the Testis 



It is well known that castration in the young prevents 

 the development of the secondary sexual characteristics 

 which normally occurs at puberty — -the voice remains high- 

 pitched ; hair fails to grow on the face ; there is an absence 

 of bodily and mental vigour. The presence of the testis, 

 therefore, exerts a profound influence upon the bodily 

 metabolism. That this influence is brought about by 

 chemical means is abundantly proved. The acquirement 

 of the secondary sexual characteristics is not prevented 

 by Ugaturing the vas, nor when the testes are removed 

 and transplanted elsewhere in the body. 



Removal of the testes in the adult leads to atrophy of 

 the seminal vesicles, prostate and Cowper's glands. 



A substance having the formula C5H14N2 — known as 

 spermine — -has been isolated and is alleged, but on uncon- 

 firmed evidence, to be the active principle. 



There is some evidence that the formation of the internal 

 secretion is the function not of the tubules but of the 

 interstitial cells. After occlusion of the vas, the former 

 atrophy, but the latter undergo no change. 



