



DIGESTION COEFFICIENTS OF FOOD MATERIALS. Fog, 
The following figures were selected as giving very close 
agreement with values actually determined by experiment, and 
were then applied to a number of actual digestion experiments 
as shown in table 58 beyond. The nitrogenous metabolic pro- 
ducts are here classed with undigested residue, thus lowering 
the coefficients for protein. 
Assumed Coefficients of Digestibility. 
Carbo- 
Protein. Fat. hydrates. 
Animal foods, - - “ - 98% 97 % 100 % 
Cereals and sugars, - - - 85% 90 % 98 % 
‘ Vegetables and fruits, - - - 80% go % 95 % 
To apply these figures we may take the food of a given 
experiment, as for instance, that of experiment No. 10, which 
consisted of meat, milk, butter, cheese, oatmeal and bread. In 
the tabular statement of details of this experiment above are 
shown the quantities of protein, fats and carbohydrates belong- 
ing to each food material. Assuming that 98 per cent. of the 
protein of the animal foods, meat, milk, butter, cheese and eggs, 
and that 85 per cent. of the protein of the oatmeal and bread 
was digested, we may calculate the amounts of protein digested 
from the total food eaten. Comparison of this with the total 
amount of protein will give the coefficient of digestibility of pro- 
tein as calculated for this experiment. The computations are 
somewhat detailed and need not be given here. ‘The result, 
however, will give a coefficient of 92.8 per cent. The coeff- 
cient as found by actual experiment was 94.4 per cent. The 
disparity between the two results amounts to 1.6 per cent. In 
the same way the coefficients for the other materials, fats and 
carbohydrates may be calculated and compared with those 
found by experiment. In table 58 such comparisons are made 
for experiments 6 and 10-14, above reported; that is to say, 
all of those in which there was a mixed diet with_a consider- 
able number of food materials. In the same table are given 
similar comparisons for experiments by Professor C. EK. Wait, 
of the University of Tennessee. hese experiments, which are 
not as yet published, belong to the series of inquiries which are 
being carried on at that institution in cooperation with the U. = 
Department of Agriculture. It is through the courtesy of the 
Office of Experiment Stations that I am permitted to make use 
of the figures here quoted. | 
