44 PRACTICAL TROUT CULTURE. 



ment we found that the spawn deposited in the 

 lowest division of the trough did equally as well 

 as those in the highest. 



From our first season we were dissatisfied with 

 troughs. Spite of all our care, dirt would find 

 its way into them, and, lying concealed amid the 

 gravel, seriously affect, by its putrefaction, the 

 health of the spawn or young fishes ; the gravel 

 being white, dead ova would too frequently escape 

 observation, and, as will hereafter be explained, 

 destroy large numbers of eggs before their pres- 

 ence could be detected. Spawn would die buried 

 in the gravel, and at the time of the emergency of 

 the young fish from the egg, a period when per- 

 fect cleanliness was most especially required, the 

 amount of filth in the troughs would be greatest. 

 Again, upon the wood a thick, gelatinous sub- 

 stance would appear, slimy to the touch and dis- 

 gusting to the eye, and which no precaution on 

 our part could prevent, though we have since 

 learned that covering the entire inside surface 

 with window-glass, bedded in pitch, has been 

 practiced with success. The difficulty of remov- 

 ing spawn for supplying customers was great, and, 

 from being buried in the damp earth, the wood 

 rotted rapidly, requiring frequent repairs. We 

 were delighted on reading of the small hatching- 

 trays invented by Mr. Caron, of France, though 



