180 FISH-CULTURAL ASSOCIATION. 
AMOUNTS OF NUTRIENTS REQUIRED IN A DAY’S FOOD. 
Mintmum daily ration for laboring men at ordinary work. 
Protein Fats Carbo-hydrates 
118 grams (4,2 ounces). 56 grams (2 ounces). 500 grams (17,6 ounces). 
The same experimental research which has revealed to us the 
ways in which our food supplies our bodily wants, has shown us 
how to estimate the relative nutritive values of different foods 
from their chemical composition. The estimates are only ap- 
proximate, because the nutritive effects are influenced by various 
conditions, some of which research has not yet been definitely ex- 
plained, while others vary with the nature of the food or the 
user, so that the value of a given food in a given case may vary 
from the standard set by the analysis. These sources of uncer- 
tainty are nevertheless so narrowed down by late investigation, 
and the errors confined within such limits, that by intelligent 
use of the facts at our disposal, we may judge very closely 
from the chemical composition of a food, what is its value as 
compared with others of the same class, at any rate, for our 
nourishment. 
CHEMICAL ANALYSIS OF FOODS. 
We are now ready to consider the amounts of the different 
ingredients, nutrients and non-nutrients, in fish and other foods. 
Perhaps I can illustrate this in no better way than by an actual 
example. A sample of beef, sirloin, of medium fatness, was 
found by analysis in our laboratory, to consist of about one- 
fourth bone and three-fourths flesh, edible substance. The flesh 
was analyzed and found to contain, nearly: water, 60 per cent.; 
protein, 19 per cent.; fats, 20 per cent.;)}mineral matter, jiaper 
cent. Calculating upon the whole sample of meat, which one- 
fourth, or twenty-five per cent., was bone and other refuse, and 
75 per cent. flesh, the analysis would stand as in the following 
table, in which the composition of the flesh by itself and that of 
the meat, bone, and all, are both given:— 
