I2 STORRS AGRICULTURAL EXPERIMENT STATION. 
results are so difficult to obtain as to make a complete com- 
pilation difficult, as indeed it is unnecessary. Of the analyses 
thus compiled not far from 1,300 have been made by the writer 
and his associates, and not far from 700 by others in connection 
with the series of cooperative food investigations now being 
conducted under the auspices of the Department of Agricul- 
ture. ‘The larger number of the rest were by the Division of 
Chemistry of the United States Department of Agriculture, 
which has also made great numbers of analyses of the classes 
of food materials of which the complete compilation was, not 
attempted for the reason just stated. 
We have thus to-day a reasonably fair idea of the chemical 
composition of the food materials most commonly used in the 
United States. Their nutritive value, however, depends upon 
not only the proportions of the different nutrients—protein, fats, 
carbohydrates, etc.—but also upon the amounts of those nutri- 
ents which can be actually digested and used by the body for 
its nourishment. The object of the digestion experiments 
above referred to is to get light upon this latter factor—that of 
the nutritive value. 
Another factor of the value of food for nourishment is what 
is called the fuel value, z. e., the amount of potential energy in 
the food which can be transferred in the body into heat, mus- 
cular power, or other forms of energy. 
Table of Percentages of Digestible Nutrients and Fuel Values 
of Foods,—While the information on these latter and kindred 
subjects now available is far from sufficient to show the exact 
values of different kinds of food for the nourishment of the 
body, enough has already accumulated to warrant the prepara- 
tion of a reference table giving the estimated average amounts 
of actual digestible nutrients in a number of the materials most 
commonly used for the nutrition of man. Such a table has 
been prepared and is printed in the present Report. As ex- 
plained in the description which accompanies this table, the 
figures are not given as showing exactly the average composi- 
tion, digestibility, and nutritive value of each class of food 
materials. Many more analyses and experiments will be 
needed to show the range of variation and the actual averages 
of both composition and digestibility. The estimates of fuel 
