102 STORRS AGRICULTURAL EXPERIMENT STATION. 

is 4.2 calories, and 98 per cent. is available. Accordingly the 
factor for 1 gram would be 4.1 calories (4.2 * .98 = 4.12). 
In Table ro beyond are summarized the factors for fuel value 
of nutrients in different groups of food materials, together with 
factors for heats of combustion, availability, etc. The method 
of deriving the quantities in the different columns is in part. 
indicated by algebraic expressions in the column headings. The 
quantities in column A represent in round numbers the approx- 
imate proportion of the different nutrients found in each of 
the different groups of food materials in the average diet as 
based upon the results obtained in an examination of 185 actual 
dietary studies. The figures are essentially the same as those 
given in Table 3 above. The figures in column B are taken 
from Tables 6, 7 and 8 above, and represent the factors for the 
heat of combustion or total energy per gram of the nutrients 
in the different groups of food materials. In computing the 
figures for the heats of combustion of total animal food, total 
vegetable food, and total food in the average mixed diet, account 
is taken of the proportional amounts of the nutrients furnished 
by the different groups of food materials as shown in column A 
and the heat of combustion of these nutrients as shown in 
column B. For example, in the ordinary mixed diet about 
43 grams out of every roo of protein is furnished by meat, 
fish, etc. This 43 grams, with a heat of combustion of 5.65 
calories per gram, supplies a total energy of 243.0 calories 
(43. X 5.65 = 243). In the same diet 6 grams of protein 
would come from eggs. This, at 5.75 calories per gram, fur- 
nishes 34.5 calories. The dairy products furnish 12 grams of 
protein, with a heat of combustion of 5.65 calories per gram, 
making 67.8 calories. ‘The total animal food thus supplies 
(43 + 6+ 12=) 61 grams of the 100 grams of the whole 
diet, and these 61 grams of animal protein contain a total of 
(243 + 34.5 + 67.8 =) 345.3 calories, which are equal to 
(345.3 + 61 = 5.651) 5.65 calories per gram. In like manner 
the 39 grams of vegetable protein are made up of 31 grams of 
protein from cereals with a heat of combustion of 5.80 calories 
per gram; 2 grams from legumes with a heat of combustion of 
5-70; 5.5 grams from vegetables with a heat of combustion of 
5.00; and .5 of a gram from fruit with a heat of combustion 
of 5.20 calories per gram. We thus have 421.3 calories 

