538 



CHAPTER XXXVII. 



MALE ORGANS OF GENERATION. TESTICLES. VASA DEFERENTIA. 



VESICUL^E SEMINALES. PROSTATE GLAND. COWPEfi's GLANDS. 



PENIS. URETHRA. GLANDS OF LTTTRE. GLANDULE TYSONI. 



VESICULA PROSTATICA. SEMINAL TUBULES. SPERMATOZOA. DE- 

 VELOPMENT OF SPERMATOZOA. MOVEMENTS OF SPERMATOZOA. 



Male Organs of Generation. The essential organ of generation, 

 or the secreting portion of the sexual apparatus, in the male, is the 

 testicle. The efferent duct is the vas deferens, which opens into 

 the membranous portion of the urethra, and connected with it are 

 the vesiculas seminales and Cowper's glands. The urethra is con- 

 tinued forwards along the lower part of the penis, or intromittent 

 organ. 



Testicles. Each testicle is rather less than two inches in length, 

 and is nearly one inch broad. Its weight is about six drachms. 

 The testicle is covered by a firm, fibrous, inelastic tunic, or proper 

 covering, the tunica albuginea or tunica propria, consisting almost 

 entirely of white fibrous tissue, in the substance of which vessels 

 ramify. It is with difficulty divided into two layers, the inner of 

 which is the most vascular. Adhering closely to the tunica albu- 

 ginea, is the visceral layer of the serous membrane, or tunica 

 vaginalis, the sac of which was originally formed by the descent of 

 the testicle from the abdomen, when it carries before it a process 

 of peritoneum. In early life, the cavities of the tunica vaginalis 

 and peritoneum are continuous with each other ; and, occasionally, 

 the opening remains unclosed in the adult. The parietal layer of 

 the tunica vaginalis is loose, and united by lax areolar tissue to the 

 other structures which form the scrotum. This layer of the serous 

 membrane admits of considerable distension; and, in disease, a 

 very large quantity of serous fluid will sometimes accumulate in 

 the sac, and distend it to a great extent (hydrocele] . 



Structure of the Gland. The secreting portion of the organ con- 

 sists of a vast number of minute and highly tortuous tubes, which 





