34 s TROUT CULTURE. 



systems fifty to sixty per cent, of vitalized eggs was 

 considered excellent ; by the dry process of spawning, 

 and the use of more suitable hatching appurtenances, 

 a per centage of eighty-five to ninety is now con- 

 sidered quite ordinary. Hatching frames or tanks are 

 constructed in almost every conceivable way, and 

 of a great variety of material, including slate slabs, 

 earthenware, iron (galvanized and otherwise), wood, 

 and perforated zinc. We ourselves find the last- 

 named material to answer the best, as by its use 

 gravel beds are rendered unnecessary, the finely 

 pierced metal admitting of each egg, when properly 

 spread out and arranged, being perfectly surrounded 

 by water. Fungus is also avoided and easily checked, 

 as its spreading is a moral impossibility if carefully 

 looked over daily. The French, it would appear, 

 were the first to discover that the use of gravel was 

 not requisite in artificial hatching. As regards con- 

 cealing the eggs, which concealment engenders the 

 spread of fungus, animal parasites, and fin disease in 

 more open water, the instinct of the parent fish, it is 

 presumed, prompts them to conceal their progeny 

 in a degree by the aid of the gravel ; but though 

 gravel be thus objectionable, it is necessary that the 

 eggs should be subjected to the action of the water 

 upon their whole surface as far as practicable. M. 

 Coste, the originator of the new system, placed the 

 eggs on or between the edges of slips of glass, syste- 

 matically arranged across the bottom of the hatching 

 apparatus ; the eggs being placed so as to admit of 

 the water operating upon all with the least possible 



