REPORT OF COMMISSIONER OF FISH AND FISHERIES. 79 
of Brookfield, Wash.; A. Booth & Co., G. W. Sanborne, Columbia 
River Packers’ Association, and Union Fishermen’s Cooperative Com- 
pany, Astoria, Oreg.; F. M. Warren and Mr. Farrell, of Portland, 
Oreg. This food was fresh and in good condition and the fry throve 
on it, but owing to the lateness of the season only about 1,000 pounds 
could be had, and it became necessary to purchase 2,880 one-pound 
‘ans of dogsalmon. Shortly after commencing the feeding of this food 
a disease broke out among the fry, causing heavy losses. The fattest 
and oldest fry died, though they were apparently sound. This dis- 
ease was undoubtedly due to the food. When first affected the fry 
would dart back and forth in the troughs as if seeking escape, but 
after 24 hours they became too weak for further effort and were drawn 
down against the screen, where they soon died. 
Various experiments were tried with canned salmon, in the hope of 
continuing its use as fish food, but without success. Shortly after- 
wards the use of liver was begun, and the disease above referred to 
disappeared. Liver mixed with mush in varying proportions, accord- 
ing to the age of the fry, and seasoned with a small quantity of salt, 
proved satisfactory and about as cheap in the long run as canned 
salmon. The mush is a mill product known as ‘‘ germea,” commonly 
used as breakfast food; it costs nearly twice as much as middlings, 
but is a stronger and better food. Mixed with ground liver, it sepa- 
rates readily in water and can easily be taken by the smaller fry. 
The fry were held as long as possible and were then planted at 
selected places, where the progress of their growth might be noted as 
far as possible. It is, of course, to be regretted that it is necessary to 
plant fry under 2 inches in length, but this is unavoidable owing 
to the immense amount of space that would be required for the rearing 
of millions. 
With the exception of the affection due to the feeding of canned 
salmon, there was very little disease among the fry. In the winter, 
though, there appeared on the yolk saes of about 1,500 fry what was 
supposed to be small air-bubbles, about the size of a pea, which held 
the fry to the surface of the water. They seemed to have no conneec- 
tion with the vital portion of the sac, however, as when pricked with 
a needle the bubbles would collapse and the fish would return to the 
water apparently none the worse from the operation. Upon applying 
a lighted match to the bubbles they would burst with a sharp report, 
indicating that they were filled with hydrogen gas only. Frequent 
and strong salt-water baths during the rearing period go far toward 
keeping the fry in a healthy condition. 
In rearing the fry a tank 2 feet deep, 3 feet wide, and 12 feet long, 
which had been built for the purpose of hatching white-fish, was util- 
ized for carrying about 10,000. The result was very satisfactory, as 
the fry had a greater depth of water in this receptacle and more room 
in which to move about, and it can be easily and quickly cleaned. 
The floor space occupied is also much less than would be required for 
