288 GENERATIVE SYSTEM. 



plugged with secretion, and so foil all our attempts to inject 

 them ; and in the young subject, before they begin to se- 

 crete, they are not sufficiently developed to admit of the exami- 

 nation. If quicksilver be suliered to pervade the arteries by its 

 own weight, it is found to return by the veins ; and in a prepara- 

 tion of the testicle of a dog at present before me, the absorbents 

 have been filled from the same source. Towards the posterior 

 end of the testicle, the seminiferous tubes assemble from the dif- 

 ferent parts of the interior, and unite into a set of larger tubes of 

 the same description, disposed after the manner of network, and 

 hence have got the name of the rete ; then, from the rete proceed 

 another set of similar tubes, still larger (about a dozen, I believe, 

 in number), from the testis to the epididymis, constituting the 

 sole medium of communication, and the principal one of connex- 

 ion, between the two : these are the vasa efferentia. In addi- 

 tion to these minutiee, we may notice that the superior border of 

 the testicle is marked by a broad wliite line : this denotes the si- 

 tuation of a supposed canal, and is generally mentioned as the 

 corpus Higlwiorianum. 



The epididymis is extended along the superior border of the 

 testicle, upon which it rests, and to which it is connected by the 

 tunica vaginalis reflexa. Its ends are bulky in comparison to 

 its middle : that receiving the vasa efferentia, the smaller one, is 

 the caput or globus minor ; the other, giving rise to the vas 

 deferens, is the globus major — the part farriers call the uut. The 

 interior of this appendage to the testicle exhibits a structure en- 

 tirely vascular. The vasa efferentia unite and re- unite until they 

 form a single duct, of whose numberless and very remarkable con- 

 volutions the globus major is entirely constituted : these tortuo- 

 sities (which, when squeezed, freely emit semen) will admit of 

 being unwound for a considerable extent, so as to have the length 

 of the duct calculated with very tolerable exactness from begin- 

 ning to end, which has been found to amount to several yards. 

 It is small at its formation, but grows imperceptibly larger in 

 making its manifold windings and turnings, until at length it as- 

 sumes the size of the vas deferens, in which it ends. Its various 

 convolutions are connected together by cellular membrane, and 

 are interspersed with a sparing supply of bloodvessels. 



The course of the semen is this: — It is secreted by the ca- 

 pillary coils of the spermatic artery, from which it is received by 

 the tubuli seminiferi : these tubes carry it into the rete, and the 

 rete discharges it through the vasa efferentia into the epidi- 

 dymis, from which it is conducted by the vas deferens into the 

 urethra. 



Formation and Descent. — It is a singular fact, that the organs 



