PRACTICAL PAPERS—FISH CULTURE. 
4*3 
each other which is seen in the newly-impregnated eggs of the 
brook-trout. But, even if left at rest, the eggs do not exhibit the 
same tendency to stick as the trout-eggs. After being washed 
they are laid in gravel troughs, or on trays similar to those used 
for hatching salmon-trout. (M. Gr. Holton has invented a new 
hatching-box for hatching white-fish, that is a great success.) For 
immediate transportation packing in moss is the best method, but 
is not practicable; and the eggs are either carried in water or 
brought ‘'dry/’ that is, on trays arranged in layers in a pail or 
box, and without the use of water cr any packing material. If 
jars are avoided, and a low and even temperature can be preserved, 
they will very well bear dry transportation. The period of incu¬ 
bation is about the same as that of the trout and salmon, being 
about sixty-five days at a temperature of forty-five degrees. 
When the young fish break out of the shell very fine wire- 
cloth is required to keep them. The eggs are onty about one- 
eighth of an inch in diameter, and the young fish when first 
hatched about five-eighths of an inch long. The umbilical sac is 
small, and in about ten or twelve days it apparently disappears. 
The Iry have no period of helplessness like the young of the trout 
and salmon, but commence to swim as soon as they emerge from 
the shell. These facts show that it is a good variety for propaga¬ 
tion in large quantities, inasmuch as it is able, like the shad, to 
take care of itself at once, and does not need the thirty or forty 
days’ care required by the brook-trout, salmon, and salmon-trout. 
As soon as set free it heads for deep water, where it is in compar¬ 
ative safety, and finds food enough for its wants. 
W r ith regard to the question of food, the small fish live on the 
minute forms of animal life found in abundance in the lakes. 
The experiment of raising the young fish on artificial food has 
been tried several times, but never successfully. The reason 
seems to be simply that the food cannot be finely enough divided. 
The young fish is almost transparent; and, by keeping a few in a 
glass jar or tank, you may see them take the food, may see it in 
their stomachs, and see the droppings passing from them. A few 
may be thus fed very easily ; but such feeding is not practicable 
on a large scale, nor is it from any reason necessary. 
Their growth varies, of course, but they may be said to be of 
