SPA WNIXG. 33 



should penetrate the eggs of the female. In order to 

 do this, the manuals recommended receiving the eggs 

 in a vessel of water ; afterwards, to receive in another 

 vessel of water the milt of the male ; and, lastly, to 

 turn the diluted milt on to the eggs. By his journal, 

 kept with scrupulous exactness, M. Vrasski convinced 

 himself that the fecundation was so much the less 

 complete, according as the mixture of the milt and 

 eggs had been the most delayed. If ten minutes 

 elapsed between obtaining the milt and the mixing of 

 it with the eggs, the fecundation failed almost entirely. 

 His observations, and the microscopic researches of 

 the eggs and milt, showed that : 



" First. When received in water at the moment of 

 issuing from the fish, the eggs absorb the water, and 

 preserve the power of being impregnated only as long 

 as this absorption is not finished : that is to say, during 

 a half hour at the utmost. Once saturated with water, 

 the eggs do not absorb any spermatozoa : but if 

 received into dry vessels on issuing from the fish, the 

 eggs remain, on the contrary, in a neutral state for a 

 lengthened time, and do not lose the power, when 

 placed in water, of receiving the spermatozoa. 



" Second. The spermatozoa of the milt, in falling 

 into the water, commence immediately, with much 

 vigour and rapidity, to make movements, which only 

 last, however, for a minute and a half, or two at the 

 most ; when this time is elapsed, only in some few 

 spermatozoa can their be seen particular movements 

 and agonized convulsions. 



"When, at the issuing from the fish, the milt is 

 received in a dry vessel, it does not change for many 

 hours, and during this interval the spermatozoa do not 



c 



