IMPREGNATION OF EGGS IN TROUT BREEDING. 605 
But the inconveniences attending this plan in its first 
shape were very great. The frames could not be made 
smaller than two feet square, as that is about the amount of 
space a trout requires for spawning. Nor could they be 
made larger, as the weight of the gravel on larger frames 
would render them unwieldly to handle. Therefore, in order 
to fill a trout race, a series of boxes— say from ten to forty 
is required. All these have to be looked over at least once 
every week during the season, and if there are many fish, 
two or three times a week. Each: time the screens are 
looked over every fish is necessarily driven from the race, 
although they may be just commencing their nests, or in the 
very act of spawning. The upper screen with its load of 
gravel is first lifted out of the water. The lower screen 
will then float to the surface if it is not water-logged. The 
eggs lying upon it are brushed to, one corner with a feather ; 
à pan is placed underneath the corner, the screen is tipped up 
and the eggs feathered into the pan sometimes, for the cur- 
rent often sends them in any direction except into the pan, 
and cold fingers are not always reliable. India-rubber gloves 
are no protection from cold, nor woollen gloves from water ; 
and the two combined are too clumsy for the purpose. After 
the eggs are taken, the fine screen is returned to its place, 
the upper sereen fitted exactly to it and both sunk again to 
their place ; unless as often happens a stone or two has fallen 
out of the frames upon the supporting ledges, in which case 
the screens have to be taken up again and the stones re- 
moved. It will take two men five or six hours to properly 
look over forty of these screens. In order to make this 
process easier the writer invented and patented what he 
calls the “Roller Spawning Box." This box answers for se- 
curing the naturally impregnated eggs of salmon, salmon 
trout, speckled brook trout, whitefish, shad, etc., etc. The 
principle used is that of the " Ainsworth Screens,” and the 
improvement consists in a new and convenient method of 
collecting the eggs. 
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