REPORT ON ARTIFICIAL FISH-CULTURE. 47 



yelk of a bird's egg, and at first, by means of 

 this substance the minnows are nourished; but 

 when - absorption takes place, the young fish have 

 need of other nutriment, and should then be driven 

 out of the box in which they are cradled, and 

 permitted to swim freely in the streamlet which 

 they are to stock. 



In fine, to procure for these little fish suit- 

 able and abundant nourishment, it is only neces- 

 sary to leave or put in the water some frogs, 

 whose spawn they will greedily eat, while the 

 tadpoles afford excellent food for the older trout. 

 When the young trout so brought up are des- 

 tined to stock a river, they should be placed in 

 streams tributary to it, and water selected which 

 rushes over pebbles or rocks. 



In proportion as these fish grow, they descend 

 spontaneously to the deep water, whither they 

 arrive only when they are sufficiently agile to 

 protect themselves against the enemies which 

 they may encounter ; while if they are at once 

 placed in the midst ,'of other voracious fish, they 

 will have but a small chance of escaping death. 

 When they are so raised in streamlets or ponds, 

 precaution must be taken to seperate the product 

 of each year from the former one, as the big 

 trout will otherwise eat up the little ones ; and 

 to avoid this the young fish in the same circle 

 should be of one age. 



