1 86 EIGHTEENTH LECTURE. 



The lymph passages keep in the spaces of the connective 

 tissue, bounded by the membranous but fenestrated combina- 

 tions of the flat connective-tissue cells. 



They form a copious reticular canal-work. In transverse 

 sections of the seminiferous canals they form regular rings 

 around the latter, with large expansions at the nodal points. 

 A continued injection finally drives the mass through the 

 spaces of the flattened cells, as far as the outer layers of the 

 walls of the seminiferous canals. The solid inner layer of 

 the latter alone prevents the further advance of the mass 

 (Mihalkovics). Here and there a blood-vessel becomes en- 

 sheathed by the lymph current, but this is not the rule. 



Larger lymph passages penetrate from the glandular por- 

 tion into the septal system and from here, coalescing, pass 

 beneath the albuginea. Having entered the latter, they be- 

 come valved vessels, which unite with those of the epididy- 

 mis. The final removal of the lymph takes place through 

 the spermatic cord. 



The testicle arises, similar to the ovary, at the inner side of 

 the Wolffian body. From its canal-work arises the epididy- 

 mis (equivalent to the parovarium) ; the efferent canal of the 

 primitive kidney, disappearing in the female, persists in the 

 male generative apparatus, and becomes the vas deferens. 

 The remainder must be left to the history of development. 



We have thus far considered only the quiescent gland. 

 Let us now, however, examine the same at the height of its 

 activity. 



Let us commence with its product, the semen, or sperm. 

 It is by no means exclusively the product of the convoluted 

 glandular canals of the testicle, but its fluid portions are cer- 

 tainly also derived from the epididymis and the accessory 

 glands, although its most important and characteristic ele- 

 ments originate from the former source. 



The whitish, thickened fluid, spread out in a thin layer on 

 the microscopic glass slide, presents a remarkable appearance, 

 which has been stared at for two hundred years, and was 

 formerly very curiously explained. 



