Preliminary Considerations. 13 



water, of which the hatching-house should have 

 an ample supply. Whether this be derived 

 from stream or spring, is of small consequence 

 so long as the temperature be not liable to 

 sudden changes, as these are likely to interfere 

 with the gradual and even development of 

 the embryo. On the whole, therefore, we are 

 inclined to prefer spring water for our hatch- 

 ing operations. For rearing the fry when 

 removed from the hatching boxes, we also 

 require pure water, water that is free from pol- 

 lutions. But it should be well stocked with 

 insects and animalcules, as these afford a 

 constant supply of natural food for the young 

 fishes. It may be stream or spring water so 

 long as these conditions are fulfilled, and the 

 more nearly it approaches in its qualities to 

 that in which the eggs were hatched, the 

 nearer will it be to perfection as a receiving 



stream. 



% 



Any little stream, possessing these characters, 



