Another portion of the expressed semen was treated with a concentrated solution of nitre. It thereby became considerably tougher, more viscid, and filtered with difficulty. On addinr, water, a milk-like cloudiness was pro ducal' in the filtered portion ; it was, how ever precipitated in the same manner as the simple watery extract by the infusion of galls. Nitric acid caused a slight precipitate of al bumen.
A second series of experiments was insti tuted on the semen from the testicles of a cock, in which, however, the spermatozoa were only scantily developed. The contents of the seminal tubes principally consisted of cells of developement, vvhich could only be separated with difficulty from the tissues of the testicles.
The filtered solution abounded in albumen, but contained, on the other hand, only a slight quantity of the matter (mucus), which was precipitable by acetic acid, and insoluble in excess of it.
The residue on the filter (cells of deve lopement and spermatozoa) was dissolved in solution of potash. The solution yielded a white precipitate with acetic acid, which principally dissolved in excess of the acid (albtuninous substance), whilst only a slight quantity remained undissolved (binoxyde of protein).
An old rabbit, when in the period of rutting, was subjected to a third series of experiments. The moderately turgid testicle was cut into pieces, and the milky semen expressed. It consisted of spermatozoa and numerous epi thelial cells. The reaction in the testicles was neutral, in the epididymis it was slightly alka line. It could only be filtered imperfectly. The filtered solution was cloudy, and con tained many spermatozoa. The presence of a slight quantity of albumen could be perceived on the application of boiling heat.
The residue of spermatozoa left on the filter, and which were only imperfectly sepa rated from the fluid, dissolved with tolerable ease in solution of potash, and were precipi tated by acetic acid. A very slight quantity only dissolved in an excess of this acid. Only a slight cloudiness was produced in the acetic solution by ferro-cyomide of potassium.
These different experiments yield the fol. lowing results :— 1. The pure semen presents the appearance of a milky fluid, of a mucous consistence, and neutral reaction. A slight alkaline reaction
was perceived only once.
2. The developed spermatozoa consist of binoxyde of protein, the same substance which Mulder has proved to be the principal constituent of the epithelia, as well as of the horny tissues in general.* 3. The spermatozoa contain about 4 per cent. of a butter-like fat, as well as phos phorus in an unoxydized state, and about 5 per cent. of phosphate of lime.
4. The fluid part is a thin solution of mucus, which, in addition to the animal matter, contains chloride of sodium and small quan tities of phosphate and sulphate of the alkalies.
5. The imperfectly developed spermatozoa are composed of an albuminous substance, the quantity of which diminishes in proportion to the progress of the morphological develope ment.
6. The perfectly developed semen contains no longer any albuminous compound..
7. The semen in fishes, birds, and mam malia possesses, essentially, the same chemical composition.
Such are the statements of Dr. Frerichs. The most important inference derivable from them appears to us to be the fact, that the spermatozoa, in their chemical composition, belong to the same category as the epithelial cells of the animal body. This fact removes every doubt respecting the nature of these formations,— every idea of their being inde pendent animals. The spermatozoa are there fore (as proved both by chemical analysis and by microscopical investigation) mere element ary constituents of the male animal body, which, like their equivalents in the female ani mal, the ova or contents of the ovaries, are distinguished from other histological elements by their having a different physiological pur pose ; they have less influence on the indivi dual in which they are produced, but are in tended, when separated from that individual, to give rise to the formation of a new coned lt is probably no false inference on our part, when we express the opinion that the.de veloped seminal elements present every where, and not merely in mammalia, birds, and fishes, the same composition. Indeed, we do not see any reason for assuming that this differs even in cases where the proper fluid is want ing, and where it is only the spermatozoa which constitute the seminal mass.