Feeding of Fishes in Confinement. 69 
whitefish; the former can, with our present knowledge, be 
fed only by introducing fresh water from a stream contain- 
ing their living microscopic food, paying no attention what- 
ever to particles washed from a piece of beef or fish, at least, 
as far as my own knowledge extends. 
Then observe the hardy California salmon how it thrives 
on liver finely chopped, although I question if chopped fish, 
earth-worms, or the small red worm from the mud of trout- 
streams, if they could be obtained in quantity, or, in fact, 
any of the softer and more easily dissolved flesh of the kinds 
named, or crustaceans, would not be better, although liver and 
the other gland, known as spleen or milt, is far softer than 
the muscular fibre of beef. Fish and shrimps are more 
easily digested by anemones, as has been shown, and most 
likely are equally suitable for fish themselves as being their 
more natural diet. 
Our young brook-trout do not do so well on liver, but in 
the first months die freely until accustomed to the unnatural 
conditions, all the weaker members, like the “good,” die 
young. j ; 
Here are instanced three kinds of fish: the first rejecting 
all that man offers that in any degree differs from what 
nourished its parents; the second growing comparatively 
well on strange food, but never making as rapid growth, 
partly owing to confinement in small space ; and the third 
occupying a position between the two, with only the “ fittest ” 
surviving. 
I cannot think that the great mortality in young brook- 
trout at the time they begin to take food is at all a law of 
nature, but rather a deficiency of some important condition 
necessary to their existence. 
While engaged in trout-culture some years ago, I fed my 
