SEMEN. 



505 



the most striking proof of this. The sperma- 

 tozoa, when enclosed in these, frequently re- 

 tain their full vitality for months. Among 

 the mammalia, likewise, the motions of the 

 spermatozoa remain unimpaired in the vagina, 

 or in the uterus, for some days after copulation. 



The mucous coat which covers these or- 

 gans has no prejudicial effect on the motion 

 and vigour of the spermatozoa*, and equally 

 as little so the addition of other animal 

 fluids, as the secretion of the prostate, the 

 serum, milk, &c. Common saliva, and even 

 bile or pus, does not exercise any impeding 

 influence upon the motions of the spermatozoa. 



The addition of urine, especially when hav- 

 ing an acid reaction, seems to have a rather 

 more injurious influence upon them, for their 

 motion ceases soon afterwards, although for 

 some hours slight traces of it may still be per- 

 ceived. 



We have already treated of the influence of 

 common water upon the spermatozoa. Diluted 

 saline solutions or sugar and water, on the 

 other hand, either do not produce these inju- 

 rious effects at all, or, at least, only in a very 

 slight degree. The chemical agents are the 

 only ones which have a positively injurious 

 effect on the spermatozoa, changing and 

 destroying their structure and composition ; 

 as for instance alcohol, acids, metallic salts, 

 &c. Diluted aqueous solutions of narcotic 

 vegetable substances, of strychnia, morphia, 

 &c., have the same effect as common water. 



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 

 Limnseus and Planorbis on treating them 

 with hot water of 70 80 (Centigrade). 



Chemical 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 man 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 



* For numerous researches on the influence of 

 reagents on the movements of the spermatozoa, 

 vid. Donne's Nouvelles Experiences sur les Ani- 

 malcules Spermat., Paris, 1837; as well as Kra- 

 mer, p. 17. In some cases, however, our own re- 

 searches have furnished a different result. 



Fourcroy, Vauquelin, Jordan, John, and Las- 

 saigne, 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 by Vauquelin. 



Under such circumstances it appeared 

 desirable to undertake 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 



