The electric spark destroys the motion of the spermatozoa instantaneously, unques tionably' because it changes their structure. Galvanism, on the other hand, remarkable to say, has no effect upon them, as Prevost states. A high or low temperature likewise causes the motions to cease, or at least to slacken, although the motions of the sperma tozoa of frogs and fishes continue when the surrounding medium sinks below zero. The same has been observed in the spermatozoa of Limnmus and Planorbis on treating them with hot water of 70°-80° (Centigrade).
Chen2ical composition of the semen. — The semen in most animals is a tough, thick, white, yellow, or darkish grey fluid, heavier than water, falling to the bottom when shaken with it. Its taste is sharp and astringent. The peculiar smell, which is usually attributed to it, is comparable with the smell of bone filings, and has its origin, perhaps, in the secre tions mixed with it. Pure semen in tam and animals does not seem to give forth any de cidedly striking smell.
The chemical analyses of semen are dated from a period when our knowledge of organic combinations was still very imperfect, and far from having attained that elevation, by which it has become equally important to physiology as the study of morphology. The works of Fourcroy, Vauquelin, Jordan, John, and Las soigne, are still the sources from which we derive our knowledge of the chemical nature of the semen.
Vauquelin, whose analysis is the most elaborate, found in the human semen ninety parts of water, one part of soda, three of phos phate of lime and chloride of calcium, and six parts of a peculiar substance (spermatine). These statements were afterwards confirmed by John and Lassaigne. Spermatine, however, the more intimate knowledge of which would have possessed the principal interest, was no further investigated than it had been pre viously Vauquelin.
Under such circumstances it appeared desirable to untlertake a new chemical analy sis of the semen, especially as the former researches had embraced the whole mass, without paying regard to the morphological constituents, or to the admixture of the prostatic secretion. To remove this defect, a series of researches has been instituted by Dr. Frerichs at our request, in the new chemical laboratory of the physiological in stitute of Gottingen, respecting which the fol lowing has been communicated to us for publication.
The most careful of these analyses was made on the semen of the carp, it being a fish which is perhaps best calculated for an inves tigation of this nature. The testicles were cut into pieces, and crushed, in order to press out the semen. Thus obtained, it presented a whitish, glutinous, or viscid mass, from which the membranous fragments were carefully removed. The residue of pure semen con
sisted of the spermatozoa, suspended in a fluid, and a few epithelial cells. It was perfectly neutral.
The corpuscular parts of the mass of semen were now separated from the fluid by filtra tion, and both were separately examined.
The fluid was colourless and clear, of a neutral reaction. The fluid at first filtered ex hibited no coagulation when boiled, nor was it precipitated by nitric acid. Albumen, there fore, was not present. The liquid which sub sequently passed through, however, on wash ing the mass, precipitated a small quantity of albumen on being subjected to a boiling heat, as also on being treated with nitric acid. Acetic acid, tannic acid, alum, and acetate of lead likewise precipitated albumen.
On being evaporated, the fluid left a yel lowish, gum-like mass with a strong fishy smell. It re-dissolved partially in water, but was precipitated from it by tincture of galls. The insoluble residue was easily dissolved by diluted solution of potash, and precipitated by acetic acid, without being again dissolved by an excess of it.
A part of the evaporated semen was burnt : there remained an ash, consisting of chloride of sodium, as also of slight quantities of phos phates and sulphates of the alkalies.
The spermatic fluid therefore resembles .a thin solution of mucus.
The spermatozoa which were left after filtration were carefully washed with water : they were thus quite pure, excepting the ad mixture of some few epithelial cells. The subject used in the investigation had attained full generative maturity,and was almost devoid of vesicles of developement.
The spermatozoa were dissolved by cold solution of potash ; a certain cloudiness which remained was due to epithelia that were slowly dissolved. The alkaline solution exhi bited a copious precipitate on the addition of acetic acid ; but the precipitate was insoluble in the excess of the acid, even by digestion. It was filtered off, and the acidulated fluid treated with potash, iron, and cyanic acid, but no cloudiness was produced. The sub stance of the spermatozoa coincides, therefore, with the " binoxyde of protein" of Mulder ; it contains no albumen or fibrin, A part of the spermatozoa were dried in a water bath, pulverised, and treated with ether. During this process they yielded a not inconsiderable quantity of fat (4.05 per cent.) of a yellowish colour and butter-like con sistence. The spermatozoa, liberated from this fat, left, on being burnt, a black coal, hich could not be made white by burning, and had an acid reaction, which was due to free phos phoric acid. The total quantity of fixed constituents, in which, besides the phosphoric acid, lime was recognised, amounted to 5.21 per cent.