SALMON AND TROUT CULTURE. 457 
hatching troughs, as the little fences which are effectual to keep 
the young fish in the troughs will also prevent the empty shells 
from floating away ; but this is the work of a few minutes only 
every day. Either the whole tray full of hatching fish may be 
turned out into a pan, and the empty shells poured off, or the 
greater part of the shells can be skimmed off with a cup or 
small muslin net ; whichever plan is adopted, it should be re- 
peated until all the fish are hatched, and the troughs are per- 
fectly clean. A few fish may have to be assisted out of their 
shells by the use of a camel’s hair pencil, as they sometimes 
hatch out ad instead of head first, and the struggles of the 
young fish to get free sometimes end in their being strangled. 
A small percentage of the fish always die in hatching, and 
must be speedily removed. Deformities and monstrosities are 
occasionally met with: some have two heads and one body 
(Salmonese Twins !) ; others have one head and a body and 
a half; a few also are hatched with three heads ; a few with 
four eyes, and some with no eyes at all.!. These are placed in 
a spare corner for observation, or preserved in spirits—they 
never live more than five or six weeks. 
There will soon be left a wriggling mass of veritable young 
trout, huddling together into every corner of the trough out of 
the light. There is no danger in this, unless the troughs are 
over-crowded with fish. In this case comes ‘gill fever,’ or 
inflammation of the gills, a plague with which I am happy to 
say I have never been troubled. The effect of inflammation of 
the gills is to eat away a portion of the gil! coverings, and if 
the fish survive, there is always trace of it to be seen in after- 
life,—nor do they ever thrive or have so good an appearance. 
A pisciculturist having anything like a demand for his 
ova will, ere this, be able to #472 out his stock considerably by 
finding unoccupied troughs; at this time also the perforated tray 
system seems to offer the greatest advantages, as the fish can 
be prevented from over-crowding by being kept in separate 
1 Two specimens, with threeheads, have been found in the writer's hatchery 
during the last eighteen years—curiously enough these were both ‘ Americans.’ 
