200 Flow to obtain it. 
seem to incommode the fish at first. Sooner or later the alevin 
loses its energy, however, drops out of the pack, and, after laying 
about for a few days, it dies. JI have not ascertained the exact 
cause of this ailment, and, as far as I can make out, it has not 
been properly diagnosed by anyone. It sometimes attacks a 
number of fish, and sometimes only a few, and is probably caused 
by coagulation or precipitation of albumen. Sudden changes and 
extremes of temperature seem to produce it in the alevins in some 
way, and it appears to attack what are otherwise healthy fish. 
Care must be taken to guard against deaths from suffocation. 
When in the egg stage, there is, under certain circumstances, a 
danger of the suffocation of the embryo, so there is a danger of 
suffocation of the alevin. Such an occurrence should never 
happen, but as it has frequently happened in the past, so it will 
happen again unless guarded against. In the old days the loss 
from suffocation was very great, when a variety of apparatus was 
used that was most unsuitable for the well-being of young trout. 
Practically, I never used anything but plain wooden boxes, but I 
have seen apparatus that suffocated the alevins by thousands. 
Tanks of wood or metal, lined with slate or glass, were of common 
occurrence, and the joints not being tight, the fish would get 
into the crevices and behind the slates in large numbers. The 
cause of suffocation in such places is that there is no current. 
The same applies in any hatching boxes when, for instance, the 
water is accidentally stopped, or if the supply be too small, although 
it is true the fish will often live a long time under such circum- 
stances. It is really simply a question of oxygen. Assoon as the 
supply available is done death takes place. A few alevins may be 
kept in a basin or a tumbler of water for a long time without 
changing the water, due regard being paid to temperature. I 
have seen a single alevin placed in a basin live three weeks with- 
out a change of water. Several of my friends who have been 
wishful to try the experiment have hatched trout ova (when well 
eyed) in a small aquarium, and have kept a few alevins there till 
the sac was absorbed, and one correspondent was successful in 
keeping the fry after feeding for several weeks, the only precaution 
taken being to ladle the water a little twice a day. As a parallel 
case I may mention having to-day, as I write, heard from an eye- 
