REPORT ON ARTIFICIAL FISH CULTURE. 39 



takes place after they have been spawned, and 

 depends inore or less upon chance. Fish belong, 

 for the most part, to the category of animals 

 among which there is '•no act of copulation for 

 reproduction, that being effected simply by the 

 ejection by the male of the milt, or semen upon 

 the eggs which have been spawned by the female. 



To procure the development of the embryo, 

 therefore, in the otherwise sterile eggs, the natu- 

 ralist, in the experiments of his labratory, has 

 only to imitate that which happens normally in 

 nature; that is to say, to bring them in contact 

 with water charged with milt ; impregnation, then, 

 is soon effected; and to procure this milt, as well 

 as the eggs to be impregnated, all that is required 

 is a light pressure of the abdomen of the males 

 and females, whose products are matured and whose 

 lives will not be endangered by the operation; or 

 these products may even be procured by opening 

 the /bodies of the newly dead subjects, for the eggs 

 and the milt preserve their vitality for some time 

 after the death of the bodies containing them, and 

 thus from two corpses may be brought forth a 

 numerous and strong generation. 



This fact was fully established by Count de 

 Goldstein, about the middle of the last century 

 long before Spallanzani published his beautiful 

 researches upon generation. In 1758 this judi- 



