

DIGESTIBILITY OF CEREAL BREAKFAST FOODS. IOI 
In making these computations it was assumed that 97 per cent. 
of the protein and 95 per cent. of the fat of milk and cream, 
and 98 per cent. of the carbohydrates of milk, cream and sugar, 
would be available;* or in other words, that 3 per cent. of the 
protein and 5 per cent. of the fat of milk or cream, and 2 per 
cent. of the carbohydrates of milk, cream and sugar were not 
available and should be accounted for in the feces. The method 
of computing the availability may be explained by use of fig- 
ures from one of the experiments. 
Data from experiment No. 558 (Table 84) are here taken for 
illustration. In this case the total amount of protein supplied 
by milk and cream was 166.3 grams, of which 97 per cent. 
was assumed to be available, leaving 3 per cent. to be found in 
the feces, or (166.3 X .03=) 4.99 grams. The total amount of 
protein in the feces from the whole diet was 32.20 gramsy, and 
the difference between this and the amount computed as due to 
milk and cream, (32.20—4.99=) 27.21 grams, was assumed 
to be due to the cereal part of the diet. Dividing the latter 
quantity by 89.55 grams, the total protein supplied by the 
cereal, and multiplying by 100, gives 69.62 per cent. as the 
coefficient of availability of the protein of the cereal alone. 
The coefficients for the other nutrients are calculated in the 
same way. 
It will be observed, however, that the results of the compu- 
tations for fat in the breakfast foods are not given. The reason 
is that the quantity of fat in cereals is so small that a slight 
error in the assumed factor for availability of fat in the rest of 
the diet makes a large difference in the computed coefficient 
for the fat of the cereal alone. 
The computation of the available energy of the cereal is like- 
wise simple, being practically the same as that for total diet 
previously explained. ‘The data consist of the total energy of 
the cereal, the energy of the feces due to cereal alone, and the 
energy lost in the urine from incomplete oxidation of the pro- 
tein of the cereal. In the case of the total diet, the energy of 
the food and that of the feces was found by use of the bomb 
calorimeter. ‘This is true of course for the energy of the cereal 

* Storrs Expt. Sta. Rpt., 1899, p. 86. 
+ For strict accuracy, the protein of total feces, computed by multiplying the nitro- 
gen in total feces by 6.25, should ‘be taken as the sum of the protein of feces from food 
other than cereal (N X 6.25) and of the protein of feces from cereals (N X5.7). This 
change would slightly increase the coefficients of availability of protein, and carbo- 
hydrates in the cereal alone over the results given in Table 87. 
