THE SPERMATOZOIDS OF THE MAMMALIA. 295 



be excited. At first, on\y a few exhibit trembling vibrations, 

 but which are soon communicated to others, and in two or 

 three minutes the whole are in motion as actively as in the 

 recent secretion. We have several times succeeded in re- 

 animating these motions of the spermatozoids, in the secretion 

 which had been retained in the epididymis three or four days 

 after the death of the animal, at a temperature varying from 

 5° to 20° Cent. If, instead of solutions of the above strength, 

 more concentrated ones are employed, the action is commonly 

 slower, weaker, and, above all, less general ; nevertheless we 

 have occasionally seen movements produced quite as rapid, 

 and also quite as general by means of a solution, containing 

 1-lOth of the salt ; a solution containing 1-iOOth of the salt is 

 usually inert. 



Chloride of sodium, is less efficient than the phosphate or 

 the carbonate of soda, inasmuch as its action is only very 

 feeble beyond 48 hours after the death of the animal. But 

 it is extremely remarkable, that a solution containing not 

 more than 1-lOOth of common salt produces the greatest 

 effect, whilst solutions containing 5, 10, and 26*4 per cent, 

 have none at all, and even solutions of 3 to 4 per cent, are iar 

 less active than those with 1 per cent. The latter surpasses 

 in efficiency the solution of sulphate of soda, which, like the 

 carbonate and phospliate, ought to be of the strength of 

 5-lOOth. Solutions containing 1 to 10 parts of the sulphate 

 in 100 have a feeble action, and the concentrated solution 

 produces none at all. Ordinarily the solution of sulphate of 

 soda, containing 5 parts in 100, is less certain in its effects 

 and less active and durable than the carbonate, phosphate, and 

 chloride, particularly if the secretion is not recent. 



As for the salts of potass, we have compared the carbonate 

 in a solution containing 5 in 100, and the chloride in one con- 

 taining 1 in 100. Their action is less constant, slower, less 

 lively and less general than that of the salts of soda. 



What has been said of the semen of the Bull does not apply 

 to that of the Frog {Bana esculenta). According to our observ- 

 ations, common salt retards the movements of the spermato- 

 zoid of the latter animal ; the phosphate and the carbonate 

 cause them to cease altogether. The spermatozoid of the Frog 

 coil up in solutions of the same salts, and at the same degree 

 of concentration, as revive those of the Bull with the greatest 

 energy. This difference recalls a fact observed by M. Moles- 

 chott, that the blood-corpuscles of birds (Fowls, Pigeons) are 

 less corrugated under the action of saline solutions than are 

 those of the Mammalia and of the Frog. 



