THE MALE GENITAL TRACT. 



813 



to dry ; and they are peculiarly resistant to the action of acids 

 and alkalies. In. the vas deferens they are motionless, there 

 being but little liquid present. Upon the admixture of mucus 

 (from the prostate) the spermatozoids at once assume a high 

 degree of activity. 



(1) The testes are compound tubular glands. The seminifer- 

 ous tubules, originally very numerous, by repeated union become 

 fewer, and at last collect into one large tubule the vas deferens. 

 The fibrous connective tissue coat, ensheathing the whole organ 

 (tunica albuginea), sends prolongations carrying the blood-vessels 

 between the tubuli ; broader septa of connective tissue are also 

 present, producing an indistinctly lobular structure in the testes ; 



FIG. 369. TESTIS OF ADULT. 



A, tunica albuginea ; V, blood-vessel; C, connective-tissue frame, carrying blood- vessels, 

 and E, E. rows of coarsely granular plastids ; TS, transverse section of seminiferous tubule ; 

 OS, oblique section of seminiferous tubule. Magnified 200 diameters. 



at their upper posterior aspect, in the corpus Highmori, the septa 

 are most developed and inclose sinuous spaces. The blood-vessels 

 are most numerous in the inner portions of the albuginea ; its 

 smooth, external surface is covered with flat endothelia, which 

 continue into the so-called serous sheath of the testes. The con- 

 nective tissue between the tubules, besides the ordinary connect- 

 ive-tissue corpuscles, holds a varying number of coarsely granular 

 plastids, which are often arranged in rows, exhibiting a brownish 



