SEMEN. 357 



consistence, and the longer it remains in the vesiculse seminales, 

 the more consistent it becomes. 



The investigations of Vauquelin, Jordan, and John have 

 elicited the following results, which, however, do not sufficiently 

 explain its chemical relations. When the seminal fluid has 

 been allowed to rest for some time, it becomes clear, more 

 fluid, transparent, and almost entirely soluble in water; if, 011 

 the contrary, it is at once dropped into water it sinks, and 

 instead of perfectly dissolving, it coagulates in threads, in the 

 same manner as if it had been treated with alcohol. This 

 coagulated matter is readily soluble in acetic acid, and the 

 solution gives a copious precipitate on the addition of ferro- 

 cyanide of potassium. 



On allowing the coagulum to remain in water, it gradually 

 dissolves therein, leaving a residue of a few flocculi. The so- 

 lution, if rapidly evaporated, gives off the peculiar odour of 

 semen, and leaves a clear glossy residue, which is opaque in 

 water, and only partially dissolves in that fluid. From the 

 portion which is insoluble in water, alcohol takes up extractive 

 matter; and the portion insoluble in alcohol dissolves in boiling 

 water, leaving a mucous residue : the solution is precipitable by 

 acetate of lead, chloride of tin, bichloride of mercury, nitrate 

 of silver, and infusion of galls. 



In semen which had stood for some time, Vauquelin found 

 four -sided prisms arranged in stellar groups, and terminating in 

 long four-sided pyramids, which Berzelius considers to have 

 been ammoniaco-magnesian phosphate. If the semen is allowed 

 to evaporate it becomes covered with a film, in which white 

 points may be observed, which are supposed by Vauquelin 

 to be composed, as well as the before-mentioned prisms, of 

 phosphate of lime. When the whole of the water has been 

 removed by evaporation, there remains a yellow, transparent, 

 elastic mass, which amounts to 10 of the weight of the semen. 



Vauquelin, moreover, states that fresh semen is soluble in 

 all acids, from which it cannot be precipitated by alkalies, and 

 conversely, that it is soluble in the alkalies, from which it is 

 not precipitable by acids : chlorine-water, however, coagulates it 

 to such a degree as to render it insoluble in water or acids. If 

 the semen at the moment of emission is allowed to fall into 

 alcohol, and to remain in it for some time, it coagulates tho- 



