80 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
There were 30,000 eggs in each basket at first. The eggs of basket No. 1 were 
from fish that were killed before spawning. Those of No. 5 were fertilized accord- 
ing to the dry process. Those of No. 6 and No. 7 were fertilized by the ordinary 
process used at Battle Creek. Nos. 1 and 7 were picked daily. Nos. 5 and 6 were 
not disturbed during the critical period. The number unfertilized among the dead 
eggs was not determined before the twenty-eighth day; therefore the last item of 
the table is only relative. To get the true percentage of unfertilized eggs it would 
probably be about right to double that given. (It can be determined whether 
addled eggs are fertilized by putting them in about 8 per cent acetic acid. The yolk 
of the egg becomes clear, and the embryo, if there be one, turns white. A strong- 
solution of common salt will clear addled eggs, but it also disintegrates very young- 
embryos. ) 
Even after the critical period has passed, the most careful handling kills some 
fertilized eggs. Several tests show that from 10 to 20 per cent of the loss after the 
critical period is in fertilized eggs that have been killed in handling. They should 
therefore be disturbed as little as possible. 
Fungus in the hatchery . — Fungus is a considerable pest in a hatchery, but the loss 
of eggs at Battle Creek traceable to this cause is very small. Numerous experiments 
were made in order to determine if the fungus would attack and destroy living eggs. 
Only on one occasion have I found a live egg attacked by fungus. This one had 
a few filaments of fungus growing on one side, and the egg had begun to die where 
the fungus was attached. Whether the egg had started to die before the fungus 
attacked it or whether it was attacked first I can not say, but all other observations 
and experiments indicate that the fungus attacks only the dead eggs. 
Fungus grows rapidly on dead eggs, and the filaments extend in all directions 
and entwine the adjacent eggs in a thick mat. This interrupts the circulation of 
the water and often smothers the eggs so matted. When eggs are smothered the 
embryo turns white before the yolk becomes addled, so that death from that cause 
can be distinguished. 
At Battle Creek, in 1897 and 1898, the baskets of eggs were gone over on the 
second and third days after spawning and all of the dead eggs picked out. They 
were not disturbed again until after the critical period, or about the twentieth 
day. This method was followed even where baskets (size, 23 by 15 £ by 6 inches) 
contained 40,000 eggs each. The number of eggs that died after the third day was 
small, and at the “breaking out,” that is, the first picking after the critical period 
at about the twentieth day, the few dead eggs were found scattered here and there 
through the baskets. Each dead egg was covered with fungus, the filaments of 
which had entangled the live eggs lying in its immediate neighborhood, holding them 
together in a bunch. It was seldom that more than fifteen eggs were held together 
in such a bunch, and the dead eggs never exceeded three or four. 
Such treatment is not recommended for other stations, as the difference in the 
character of the water supply makes it necessary to carry on separate investigations 
for each station in order to determine methods of treatment. 
The reason Battle Creek is so free from fungus is that the water contains a 
considerable quantity of silt or dirt, and if the eggs are left undisturbed a couple 
of days they become covered with a fine sediment. This collects on the fungus, 
which acts as a kind of filter, making of it a black muddy mass and impeding its 
