8 74 
METABOLISM. 
Foodstuff. 
Proteid. 
Fat. 
Carbohydrate. 
Apples 
0-4 
13 
Carrots 
1-1 
0-2 
9 
Potatoes . 
2 
o-i 
20 
Human milk 
2 
4 
6 
Cabbages . 
3-3 
0-7 
7 
Cow's milk 
3-4 
4 
5 
Rice . 
8 
9 
77 
Maize 
10 
4-6 
71 
Wheat 
12 
1-7 
70 
White of eggs 
13 
0-3 
Fat pork . 
15 
37 
Yolk of eggs 
16 
32 
Fat beef . 
17 
26 
Fish (pike) 
IS 
0-5 
Lean beef . 
21 
1-5 
Peas . 
23 
1-8 
53 
Heat value of foodstuffs. — A most important determination to be 
made regarding any diet is its caloric (calorific) value. This is arrived at 
by multiplying the number of grammes of its several organic constituents 
by a number, determined by exact experiment, representing the amount 
of heat produced by the oxidation of 1 grm. of the carbohydrate, fat, or 
proteid to water and carbon dioxide and to urea. Such calorimetric 
experiments were first carried out systematically by Frankland, 1 who 
determined the caloric value of various articles of diet, and his results 
have since been extended and confirmed or amended by various 
observers, 2 using improved calorimetric methods. 
According to Eubner, the average caloric value of the proteid of the 
aliment is 4124 calories, i.e. 1 grm. proteid oxidised to urea yields 4124 
grm. degrees (or 4 - l kilogram-degrees) of heat ; of the fat, 9321 calories 
(9 - 3 kilogram-degrees); and of the carbohydrate (starch), 4116 calories 
(4-1 kilogram-degrees). Applying these numbers to Voit's diet (see 
next page), we obtain in round numbers — 
105 grms. assimilated proteid x 4 - l = 430 
56 „ fat x 9-3 = 520 
500 „ carbohydrate x 4"1 = 2050 
= 3000 kilo-calories, 
or 3,000,000 calories, as the energy value per diem of the food of a man 
of about 70 kilos., doing hard muscular work. 
This amount is probably a little too high, since the whole of the fat and 
carbohydrate of a mixed diet is not assimilated. Rubner estimates the actual 
production at 2,843,000 calories. Hultgrcn and Lantergren, however, found 
that Swedish workmen, of an average weight of only 67 kilos., consumed on an 
average per diem 159 grms. proteid, 93 grms. fat, and 570 grms. carbohydrate, 
which, even allowing for the non-assimilation of a certain proportion of each, 
would still give a higher caloric value for the total foodstuffs. Probably, 
1 "On the Origin of Muscular Power," London, Edinburgh, add Dublin Phil. Mag., 
London, 1866, vol. xxxii. p. 182. 
2 Stohmann. Journ. f. prakt. Chem., Leipzig, 1879, Bd. xix. S. 115 ; Ztschr. f. Biol., 
Munchen, 1894, Bd. xxxi. S. 364; Danilewsky, Arch. f. d. ges. Physiol., Bonn, 1885, Bd. 
xxxvi. S. 237 ; Rubner, Ztschr. f. Biol., Munchen, 1883, Bd. xix. S. 313 ; 1885, Bd. xxi. 
S. 250 u. 337 ; 1886, Bd. xxii. S. 40 ; 1894, Bd. xxx. S. 73. 
