ARTIFICIAL IMPREGNATION. 83 



upon coming in contact with the water, absorption 

 takes place through the membrane, in a manner 

 known to scientists as "endosmosis," and the eggs 

 rapidly assume a full, round, and plump figure. 

 It is during this absorption that the spermatozoa, 

 with which the milt of the male is filled, pass in 

 with the water and vitalize the egg. It is therefore 

 evident that after the absorption has once taken 

 place, any attempt at fertilization would be useless. 

 The spawn, until the process of absorption is fin- 

 ished, adhere to each other and to the bottom of 

 the pan. It was formerly supposed, and we our- 

 selves have repeatedly stated it, that the spawn 

 were agglutinated together by means of a gummy 

 substance insoluble in water, and only soluble in 

 the milt of the male. This, recent observation has 

 proved to be a mistake. The egg membrane not 

 being filled, the sides are flattened by pressure 

 against each other, and adhere by cohesive attrac- 

 tion ; when full, this surface is reduced to mini- 

 mum, and the eggs are readily separated. This 

 freeing of the spawn, as it is termed, shows that 

 absorption has been finished, and that they have 

 obtained all the vitalization which they are capable 

 of receiving. The experiments of Mr. Vrasski 

 upon this subject are excessively interesting. His 

 first essays were upon the system laid down in the 

 primitive French works upon fish culture, in which 



