VESICUL^S SEMINALES. 



1431 



irregular columns and grooves, more marked 

 in their upper part, and deficient at the lower. 

 On their outer and anterior aspect is a pe- 

 culiar muscle, arising from their neck and 

 middle portion, and spreading out over their 

 upper part, which can contract their cavity 

 and expel their contents. Their ducts join 

 the vasa deferentia beneath their ampullated 

 portion noticed below. In the boar they each 

 consist of a great number of lobes and lobules 

 arranged around, and communicating with, a 

 small central canal, which opens on the veru- 

 montanum, near the vas deferens. 



It may not be out of place here to mention 

 several remarkable peculiarities in the structure 

 of the vasa deferentia, when they arrive at the 

 back of the bladder, in several animals. In man 

 this part of them is dilated and sinuous, and 

 generally contains a fluid very similar to that 

 found in the vesiculae. In the horse this 

 part of the ducts is extremely thickened by 

 the occurrence of numerous glandular cellules 

 in its walls. These cellules contain a thick 

 mucus. Much the same condition is met 

 with in the bull. In the elephant each vas 



jferens, when it arrives at this part, enlarges 

 ito a very large cavity, which it is evident 

 lay readily, and no doubt does really, fulfil 

 ie function indicated by the words vesiculae 



ninales. 



FUNCTION. With regard to the function 



these organs, I am able to come to little 



>re than a confimation of the negative con- 

 clusion of Hunter, that they are not reservoirs of 

 semen. Hunter's positive conclusion that they 

 form part of the generative apparatus, is pretty 

 clearly proved. I proceed to offer the evi- 

 dence from which these two conclusions are 

 arrived at. 



1st. They are not reservoirs of semen. That 

 they were receptacles into which the semen 

 might regurgitate and be stored up ready for 

 emission, was doubtless suggested by their con- 

 nection with the vasa deferentia in the human 

 subject, so like the relation of the gall bladder 

 to the hepatic duct. A very obvious objection 

 to this is that, as we have seen, the same relation 

 does not occur in the majority of animals ; 

 but the difficulty of proving the identity of 

 the sacs called vesiculae in other animals, 

 diminishes very much the force of this ob- 

 jection ; and even if a homological identity 

 were proved, still numerous caveats warn us 

 not therefrom to infer their functional identity. 

 It is moreover extremely easy to conceive the 

 possibility of the regurgitation of semen into 

 the vesiculae, where the two ducts have an out- 

 let, though merely an outlet, in common. (In 

 such cases they join just in the act, so to 

 speak, of debouching.) And it is far from 

 impossible to conceive the regurgitation of 

 semen even when the outlets are distinct, 

 especially in some instances. In the guinea- 

 pig, for example^ the outlets of the vasa defe- 

 rentia, vesiculae seminales, and prostatic ducts, 

 are surrounded by occur in the bottom of 

 a little spout, of about a line in diameter, 

 which projects about half a line into the ure- 

 slanting towards the outlet. Another 



objection to their being reservoirs of semen 

 is that the fluid found in them is extremely 

 different from that found in the vasa dr- 

 ferentia, as observed by Hunter, in colour, 

 consistence, and smell ; but that they should 

 secrete a mucus of their own, is only pa- 

 rallel \viih what we know to be the case in 

 the gall bladder ; and that admixture with 

 this mucus should considerably alter the 

 character of the semen, is extremely pro- 

 bable. To a microscopic examination of the 

 contents of the vesiculae, we naturally look 

 for a solution of this question, now that we 

 know the extremely characteristic microscopic 

 appearance of semen Arc spermatozoa found 

 in it? 



Miiller says " That the vesiculae seminales 

 are really receptacles of semen, is beyond a 

 doubt, since spermatic animalcules have been 

 discovered in their contents in the human 

 subject after death." * To the fact, that 

 spermatozoa are occasionally found in the 

 contents of the vesiculae, I can add my 

 testimony ; but I am compelled by other 

 facts to dissent from the conclusion at which 

 Miiller arrives. To infer that the proper 

 function of the vesiculae is to serve as re- 

 servoirs of semen, because spermatozoa "have 

 been" found in them after death, is a non 

 sequitur. Spermatozoa may often be found 

 in the urethra, and I have found them in the 

 urinary bladder. These restless little entities 

 often wriggle themselves into organs where 

 their presence is far from usual or normal. 

 Even after death they may be forced into the 

 the vesiculae by the violence unavoidable 

 in removing the parts for examination. The 

 question is, are they usually found in the 

 contents of the vesiculae, and that in large 

 numbers? To answer this question I thank- 

 fully avail myself of the more extensive obser- 

 vations of my friend, Mr. J. Quekett, who 

 carefully examined the subject some years 

 ago. He tells me that the presence of sper- 

 matozoa in the human vesiculae is not very 

 frequent, even when the sacs are very dis- 

 tended by their contents j and that when 

 they are present, it is in sparing numbers 

 in fact, as a few stray ones. This accords per- 

 fectly with the results of my own researches. 



When I find the vesiculae seminales full to 

 distension with a mucous fluid, and discover, by 

 a microscopic examination, only a few solitary 

 spermatozoa in it, and when I compare this 

 with the crowds of spermatozoa seen in the 

 fluid squeezed from the vas deferens, I cannot 

 believe, even allowing a reasonably broad 

 margin for dilution with mucus, that I am ex- 

 amining stored semen. In the lower animals 

 I have never observed a single spermatozoon 

 in the contents of their vesiculas seminales, 

 although I have carefully examined it taken 

 from individuals that had been purposely sub- 

 jected to prolonged sexual excitement un- 

 grarified. My observations, however, have been 

 entirely confined to those brute animals the 

 ducts of whose vesiculae do not join the vasa 



* Physiology. Translation by Baly, p. 8i84. 

 4 Y 4 



