Feeding of Fishes tn Confinement. aT 
food is insects, fish, and crustacea; how different, and how 
easily it is passed; compare also the appearance of the vents 
of the two fishes: one small, with its edges sharply and 
clearly defined, and the other large, swollen, and hemer- 
hoidal in appearance. This, however, is only a mechanical 
objection ; for as fish contain much phosphorus, they must 
require a supply of it in their food, instead of the nitro- 
genous element so plentiful in beef. 
At our last meeting I exhibited to the Association the 
results of an experiment in keeping quinnat salmon at dif- 
ferent degrees of temperature, and the wonderful difference 
in their size at three months old. I also made another one 
not reported, I fed a few on curd, but they did not do 
as well as those fed on liver; in fact most of them died at 
five months old. It is well known that salmon, though a 
very oily fish, has but little of that commodity in its liver, 
while the cod has plenty there, but only a small quantity in 
its body. These little fish seem to have an oily liver, much 
increased in size, without a corresponding increase of the 
gall-bladder, and while their general condition was poor, the 
intestines were loaded with fat. 
I have found that gold-fish grow best on a mixed diet of 
worms and vegetation, especially those low forms growing in 
stagnant waters, on stones, etc., called confervz, and also 
that a sea-fish, known. as mullet (muzdl lineatus) does not grow 
in size in aquaria if fed on fish alone, as they are mainly 
vegetarians, feeding on the red sea-weed, known as fucus, 
and which can only be grown in dark places. This was 
told me by several aquarium curators in Europe. 
As another instance of the effect of feeding, I will say 
that I fed two small crabs on fish, and two on beef for four 
months; the former cast their shells and grew, while the 
