320 GENERATION. 



by Giraldes as a remnant of the "Wolffian body, analogous to 

 the parovarium. 



Vesicidoe Seminales. Attached to the base of the blad- 

 der and situated externally to the vasa deferentia, are the 

 two vesiculse seminales. These bodies are each composed of 

 a coiled and sacculated tube, from four to six inches in length 

 when unravelled, somewhat convoluted, in the natural state, 

 into an ovoid mass which is firmly bound to the vesical wall. 

 The structure of the seminal vesicles is not very unlike that 

 of the sacculated portion of the vasa deferentia. They have 

 an external fibrous coat, a middle coat of muscular fibres, and 

 a mucous lining. Muscular fibres pass over these vesicles 

 from the bladder, both in a longitudinal and in a circular di- 

 rection, and serve as compressors, by the action of which 

 their contents may be discharged. The mucous coat is pale, 

 finely-reticulated, and is covered with cells of polygonal epi- 

 thelium, nucleated and containing brownish granules. JSTo 

 mucous glands have been found in its substance. 



The vesiculse seminales undoubtedly serve, in part at 

 least, as receptacles for the seminal fluid, as their contents 

 often present a greater or less number of spermatozoids. 

 The essay of John Hunter on the vesiculse seminales, first 

 published in 1786, in which the idea was advanced that they 

 did not serve as receptacles for the semen, showed that they 

 produced an independent secretion which became mixed with 

 the product of the testicles in ejaculation ; but this opinion 

 was not based upon microscopical observations, and the pres- 

 ence or absence of the spermatozoids was not noted. 1 Al- 

 though the mucous membrane of the vesicles seems to pro- 

 duce an independent secretion, the presence of glands has not 

 been demonstrated. The fact that the fluid capable of fecun- 

 dating the ovum is produced only by the testicles, that the 



1 HUNTER, Observations on the Glands situated between the Rectum and Blad- 

 der, called Vesiculce Seminales. Observations on certain Parts of the Animal 

 (Economy, London, 1792, p. 31, et seq. 



