66 THE NEW ART OF BREEDING FISH. 



of their existence possess all the nutriment they need 

 in the umbilical bladder ; and next, they could not 

 take and assimilate other food, if furnished them, 

 their intestines not being sufficiently developed to 

 receive and digest it. 



Independently of its uselessness, the practice of 

 furnishing food too soon may be really hurtful, espe- 

 cially if the young fish, artificially obtained, are con- 

 fined in large numbers within restricted limits. Ani- 

 mal matter furnished them, no matter in how small 

 quantity at first, not being consumed, accumulates 

 day by day at the bottom of the vessel, and in the 

 end becomes corrupt, and thus, as I have seen seve- 

 ral examples, becomes a cause of mortaUty. 



No matter, therefore, what kind of fish may be 

 obtained by artificial means, there is no necessity to 

 provide them with food until after the disappearanee 

 of the umbilical bladder. That most voracious spe- 

 cies, the pike, even, is subject to this law, and I have 

 now under observation some of that species hatched 

 twenty days ago, which, having yet traces of the 

 umbilical bladder, do not seek for food. 



With regard to salmon and trout it is not enough 

 to know when the young should be provided with 

 food, but also what kind of food should first be given 

 them. This problem, on the solution of which de- 

 pends the success of fish culture on a great scale, 

 seems to me to have been resolved by the numerous 

 and varied experiments made at the establishment 



