TROUT BREEDING. '29 



worms on certain weeds, and minute Crustacea, or when 

 they are bountifully fed, they are edible in April. In the 

 streams of the forest however, they are seldom in season 

 before the 10th of May. The peculiar habits, appearance, 

 and condition of trout at spawning time can be observed in 

 clear ponds where they are kept for breeding, as well, or 

 perhaps better, than in their wild haunts. 



Water Supply. Spring water, whether hard or soft, if 

 not impregnated to any great extent with mineral, is best, 

 not only for hatching but also for supplying ponds. The 

 warmer the water the more rapid the incubation, though a 

 low temperature conduces to the healthy condition of the 

 ova during this process, as well as to that of the young fish 

 until the umbilical sac is absorbed, as it is not favorable to 

 the growth of byssus and confervia. In proof of this I 

 would instance the small percentage of eggs lost in incuba- 

 tion by Mr. Ainsworth; though much of his success in 

 hatching is to be attributed to his experience in expressing 

 the spawn and milt, as well as the care he bestows on the 

 ova after taking them. A spring with a deep source will 

 furnish water of almost unvarying temperature, and will 

 indicate the mean of the atmosphere in its locality. In the 

 neighborhood of Philadelphia, this is about 51 or 52. 

 For hatching, the water should never be above 54 ; 46 

 or 47 is perhaps the best temperature. Spring water is 

 almost indispensable in hatching, as few or no brooks are 

 uniformly clear, or have not more or less dirt or vegetable 

 fibre carried along by the current. 



It is to be supposed that the beginner has a spring of 

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