72 
some particular case), for the preparation of the food and 
the feeding of it to the fish can safely be intrusted to the 
care-taker, who looks after the brood stock and other 
property. 
There are among fishes, in common with other animals, 
several dietaries, some followed from a matter of choice, 
some from necessity, and others from ignorance on the 
part of the attendant. They may for convenience be thus 
classified: First, bare subsistence diet, merely sustaining 
life and resulting in stunted, deformed fish or starvation ; 
second, healthy diet, promoting normal growth and de- 
velopment; third, fattening diet, fitting for heaviest mar- 
ketable weight, and fourth, over-fattening diet, causing a 
temporary or permanent suppression of the functions of 
the reproductive organs, a partial or total destruction of 
the eyes and inflammation of the intestines, frequently re- 
sulting in death. The first and fourth of these diets have 
killed very many fish, the second has hurt none and the 
third is outside the proper object of this paper. The ques- 
tion largely turns upon what constitutes a healthy diet ? 
What does it cost? and is that cost excessive? No phase 
of this question is more obscure, more diversified in prac- 
tice or richer in possibilities. 
In the following paper, wherever reference is made to 
the ‘‘daily rations,’’ ‘‘allowance,’’ or ‘‘formulas,’”’ the 
amount and proportions given apply to yearling trout un- 
less otherwise stated, the intention being to express only 
the artificial food supplied without taking into account the 
natural food the fish secure.. Nor have I considered the 
highly important though ever-varying elements of ‘‘initial 
vitality,’ ‘‘range,’’ and ‘‘ space”’ in discussing the growth 
and size acquired by fish at different establishments. It 
will rarely or never happen that these conditions are iden- 
tical at different establishments, for we know that at any 
one they are found varying from year to year and fre- 
quently in the same season. In our considerations of ar- 
