500 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



as possible to tbe bottom of the box into which it is to go, and pour it 

 directly mi this bottom. In this operation, care must be taken that the 

 eggs do not lie on each other in layers. If among the eggs there is a 

 little coagulated milt, it ought to be first washed out. 



The apparatus for incubation and the hatching of young fish are very 

 different. Every pisciculturist has his own models made to suit local 

 convenience and his own individual ideas. The apparatus also varies 

 according to the species of fish ; the trout, the lavaiet, the salmon, for 

 instance, requiring cold running water, the incubating-apparatus must 

 answer these conditions. 



The article of this kind which is most used, on account of its answer- 

 ing its purpose best, is that of Coste. It is about li feet long and 1^ 

 broad and deep. The lid is formed of two parts, which open by hinges ; 

 these two panels have each a square opening, closed by a net-work of 

 metal ; the two straight sides of the box have also doors with openings 

 like those of the lid, likewise furnished with the net-work of metal- 

 Inside the box, at the ends and in the middle, there are cross pieces of 

 wood, on which other frames' are placed, which are the most essential 

 pieces of the apparatus; these frames consist of thin plates of glass in 

 wooden frames ; as many as four of these are placed on the same cross- 

 l)ieces, and the fecundated spawn is put on these glass plates. On the 

 bottom of the box sand is put, in case some eggs should escape through 

 the small spaces between the strips of glass. This arrangement has the 

 advantage, above all others, of being easily cleaned, and not bringing the 

 spawn into immediate contact with the metallic sides, which might 

 make it cold, might tear its delicate skin, and might jeopardize the life 

 of these frail creatures. 



For propagaMng fish on a large scale, the above-described apparatus, 

 and other similar ones, are replaced by special iucubating-canals, into 

 which water is led from a spring or a pond. The arrangement of these 

 canals is very simple; the water flows through a series of wooden or 

 stone basins, covered Avith a net-work, to avoid all obstruction. In these 

 basins the spawn is deposited on glass grates. 



To incubate spawn in localities where there is no running water, other 

 apparatus is used, the most common being that of Coste. This con- 

 sists of a filtering-apparatus, which leads the water, through a pipe with 

 a cock, into one or two basins made of sandstone or delf, on whose 

 bottom gravel is placed; at the end of this basin the current divides 

 into two, and, through small gutters, the water flows into troughs of 

 sandstone, placed one over the other and parallel to each other ; every 

 one is provided with a slope or gutter on the side opposite to that where 

 the water flows in. In this manner the water which comes from the 

 delf basin and which flows through this whole system of basins forms 

 an artificial brook. After having flowed through this whole apparatus, 

 this water is collected in a special reservoir destined for the fish which 

 have just been hatched, and from there it flows out. 



