PROPAGATION OF FISH. 251 



After the eggs have lain in the water from fifty to sev- 

 enty-five days, according to the temperature, the trout 

 will begin to make their appearance, the egg appears to 

 be endowed with Kf e, and the motions of the trout inside 

 "kicking" against the shell to force a way out can be 

 plainly perceived without the use of a microscope. At 

 length the trout forces his way through, head first or tail 

 first, those that hatch head first always dying, however, and 

 the useless shell floats away down stream. The trout is 

 then about one-half inch long, and the body proper as thin 

 as a needle; the most prominent features being a pair of 

 eyes, huge in comparison with the rest of the body, and 

 a sac nearly as large as the egg. This sac is attached to 

 the belly of the fish, and contains food, which the fish 

 gradually absorbs. If the fish are hatched in fifty days, 

 the sac lasts about thirty, if in seventy days, about forty- 

 five. At this period of their lives they will work down 

 into the crevices of the gravel and along the sides of the 

 troughs and stay there, nature seeming to give them the 

 instinct at this weak and defenceless period of their lives, 

 when they are burdened with a load which they can 

 hardly carry, to get out of sight and out of the way of 

 harm. 



The most critical period in the life of a trout com- 

 mences when the umbilical sac is absorbed. More, perhaps, 

 die from the time they begin to feed until they are six 

 months old, than at any other time. In consequence 

 many difEerent plans for nurseries have been suggested 

 and used. The fry require a largely increased supply of 

 water, but where only a moderate number is to be raised, 

 in place of erecting other and wider troughs or boxes for 

 nurseries, the better plan is to put only a few eggs, say 



