53 



each degree colder takes five days longer, and each de- 

 gree warmer five days less. The difference however in- 

 creasing as the temperature falls, and deminishing as 

 it rises. The best temperature for hatching is between 

 thirty-five and forty-five degrees. We are inclined to be- 

 lieve that the fish hatched at a temperature of about forty- 

 five degrees and taking from seventy to seventy-five days 

 to hatch, are stronger and longer lived, than those hatch- 

 ed in fifty days at fifty degrees. It may be well, al?o, 

 to note that the eggs earliest taken produce the best 

 fish. The water of a spring can be reduced in tem- 

 perature in winter by letting it run for a short distance 

 exposed to the open air, or it may be collected in a pond 

 and the supply either drawn from the poad or the 

 stream whichever is regarded as the most desirable. A n- 

 other .reason for delaying the hatching of trout is to 

 bring them well into spring before they are turned 

 loose, as at that time they can get more abundant food 

 than they could earlier. 



Geowth in the Egg. — A great mistake is often made 

 where eggs are to be distributed in retaining them too 

 long after impregnation. This is sometimes done for 

 convenience in shipping,' and sometimes with a view of 

 shortening the operation of hatching in the hands of 

 the person receiving them, but it is all wrong. 



About the twentieth day, the young fish can be plain- 

 ly observed in the egg. Put a few eggs in a small 

 phial and with a magnifying glass the formation of the 

 fish can be easily seen. Fish farmers should send the 

 eggs away at this time. Some of the eggs are not im- 

 pregnated and at this stage of growth may easily be 

 distinguished from the others. The dead eggs will turn 

 to a milk or a pearl white color, and should be removed 

 with the nippers as fast as they are discovered. If left 



