VESICUL^l SEMINALES. 



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fin< 



i 



same moment, so that the mucus and semen 

 shall mix in the act of escaping into tin; 

 urethra, and they do mix in a remarkably per- 

 fect manner in the little spout-like verumon- 

 tanum of the guinea-pig, then the immediate 

 solidification of the mucus docs not occur. 

 Whether this curious effect of their mixing is 

 due to the mechanical whipping of the sperma- 

 tozoa or to a specifia solvent power for mucus 

 in the semen, must remain undetermined at 

 present. 



The degree of liquefaction produced seems 

 to he much greater than what would be due 

 to simple admixture, that is to say, it is much 

 greater than would be produced by adding a 

 drop of water equally small to a mass of gum, 

 for instance, equally thick and equally large. 

 This throws fresh light on some observations 

 of Hunter's, made upon guinea-pigs. He 

 killed a male (which, by the way, he had 

 castrated on one side six months before), 

 immediately after it had copulated, and he 

 found the vesiculae of both sides full. He 

 also killed a female immediately after she had 

 received the male and " examined with atten- 

 tion what was contained in the vagina and 

 uterus; in neither," he remarks, "could I 

 find any of the mucus of the vesiculae, which 

 m its firmness must have been easily de- 

 cted." He regards these facts as proof 

 at the contents of the vesiculas are not 

 itted in copulation ; but that part of the 

 oof based on the non-detection of thick 

 mucus in the vagina and uterus is, of course, 

 much weakened by the fact of the liquefying 

 property of the semen. The other part of 

 his proof, derived from the fullness of the 

 vesu-ulae immediately after coitus, is, perhaps, 

 answered by the following observations. The 

 vesiculas are never found empty except when 

 they are diminished during the periodic rut 

 in certain animals in fact they seem to all 

 appearance equally full at all times, but here 

 no doubt appearances are deceitful ; they 

 contract and expand according to the volume 

 of their contents, so that they are never flaccid, 

 and always appear to be as full as they can 

 be. I have observed them exceedingly full 

 and large in an animal just killed, and "have 

 watched them contracting under the stimulus 

 of exposure to cold air, and when nearly the 

 whole of their contents have been expelled by 

 the contraction, they have still appeared to be 

 quite full, I should have considered them to 

 be so if I had not actually seen them expel 

 their contents. It is evide'nt that the whole 

 contents of the vesiculae are not emitted in 

 one copulation, but there is strong reason to 

 believe that a part is. 



The semen which can be squeezed from 

 the vas deferens is miik white and has very 

 little if any viscosity. Now Hunter de- 

 scribing emitted semen says, " the semen first 

 discharged from the living body is of a bluish 

 white colour, in consistence like cream, and 

 similar to what is found in the vasa deferentia 

 after death (?); while that which follows is 

 somewhat like the common mucus of the 

 nose but less viscid. The semen becomes 



more fluid upon exposure to the air, particu- 

 larly that first thrown out." Here then is u 

 mucus, which very probably is from the 

 vesiculae. 1 am convinced that it docs not 

 exist in the semen of the vas deferens. 



The mucus of the vesiculae, examined in 

 the guinea-pig, is not soluble in water. The 

 urine of the animal seems to solidify it in an 

 extreme degree, for if a little of it gets into 

 the urinary bladder it becomes as hard as 

 spermaceti. Boiled in water it shrivels up 

 slightly, but is not in the least degree dis- 

 solved. I dissolved it by repeated boiling in 

 solution of potash, by which means I pro- 

 cured a perfectly limpid, colourless solution. 

 This yielded no precipitate on the addition of 

 acetic acid. In neither of these respects, 

 therefore, does it differ much from the ordi- 

 nary varieties of mucus. (See Art. Mucus, 

 Vol. III. p. 482.) Submitted to microscopic 

 examination, I have found it to consist of a 

 very sparing quantity of fluid, in which are 

 suspended little conglomerated masses of trans- 

 parent solid, just visible by the naked eye. 

 The majority of these are of a pretty uniform 

 volume, and appear, when magnified fifty dia- 

 meters, about the size of duck shot; there are, 

 however, much larger ones and much smaller. 

 Their general contour, whether they be large 

 or small, is spherical, and they have a nodulated, 

 m ulberry-like surface, as if composed of smaller 

 bails. The smaller component balls have also 

 an irregular, granular surface, and neither they 

 nor the large conglomerate spheres show any 

 distinct trace of being enclosed in a cell-mem- 

 brane. I have, however, sometimes observed 

 numerous nucleated cells in a portion taken 

 from the fundus of the organ. But often I 

 have sought for these in vain. I have never 

 found them when the vesiculae have been ex- 

 ceedingly full and distended, in which circum- 

 stances, most probably, secretion would be 

 arrested, and perhaps even absorption going 

 on. These cells are about the size of the 

 smaller (component) spheres. I am tempted 

 by these observations to conclude that the 

 cells I met with were the secreting epithelia 

 of the vesiculas, and that becoming filled with 

 inspissated mucus (?) they conglomerate them- 

 selves into larger spheres. 1 found it con- 

 venient in making these examinations some- 

 times to add a little wrfite of egg, which pro- 

 duces no alteration in the appearances beyond 

 a greater isolation of the spheres. When 

 water is added, the outlines of the spheres 

 become much more distinct, showing a greater 

 difference of refraction of light, and there be- 

 come percept. ble very numerous insoluble 

 globules, which have a great tendency to 

 coalesce, and appear very much like oil ; their 

 refractive power is, however, less, and there 

 are other reasons for doubting that they are 

 really globules of oil. When semen is mixed 

 with this secretion of the vesiculae, the spheres 

 are still visible, and the spermatozoa are seen 

 disporting in the fluid between them. No 

 solution of them is clearly detectable. This, 

 however, it should be observed, is when the 

 mixture is exposed to cold, &c. in examination; 



