334 
ANIMAL HEAT. 
estimation of the production of heat during a complex chemical change, 
involving combination and decomposition, it is only necessary to 
consider the first and final conditions of the substances, whatever may 
have been the intermediate stages. 1 
The determination of the heat produced or absorbed by chemical 
change is made by enclosing the acting substances in a chamber sur- 
rounded by water or mercury, the rise or fall of temperature in which 
indicates the amount of heat produced or absorbed, as the case may 
be. 2 
The. heat of combustion of substances of physiological interest has 
been determined by various observers ; 3 the following table gives the 
values of some of the most important substances : — 
Substance, 
1 grm. (dry). 
Heat of 
Combustion. 
Authority. 
Substance, 
1 grm. (dry). 
Heat of 
Combustion. 
Authority. 
Hydrogen 
33,881 cal. 4 
Andrews. 
Casein . . 
5,855cal. 
Danilewsky. 
?> • 
34,662 ,, 
Favre and Sil- 
bermann. 
,', ■ • '■ 
5,867 ,, 
5,849 ,. 
Stohmann. 
Carbon . . 
7,900 ,, 
Andrews. 
Cows' milk . 
5,733 ,, 
Danilewsky. 
, , Wood- 
J8,080 ,, { 
Favre and Sil- 
Women's milk 
4,837 ,, 
charcoal 
bermann. 
Fat ... 
9,686 ,, 
>> 
Cheese . . . 
6,114 ,, 
Frankland. 
,, ... 
9,423 ,, 
Rubner. 
Potatoes . 
3,752 ,, 
Dextrose . . 
3,939 ,, 
Rechenberg. 9 
,, . . 
4,234 ., 
Danilewsky. 5 
Maltose . . 
4,163 ,, 
,, 
Lean beef . . 
5,313 ,, 
Frankland. 
Milk sugar . 
4,162 „ 
>> 
• • 
5,724 ,, 
Danilewsky. 
Starch . 
4,479 ,, 
!> • • 
5,641 ., 
Stohmann. 6 
,, ... 
4,182 „ 
Stohmann. 
!) ' 
5,656 ,, 
Rubner. 7 
Cane-sugar . 
4,176 ,, 
Danilewsky. 
White of egg 
4,896 ,, 
Frankland. 
Glycogen . 
4,190 ,. 
Stohmann. 
Yolk of egg . 
6,460 ,, 
,, 
Cellulose . 
4,185 ,, 
,, 
Butter . . 
7,264 ,, 
Urea . . . 
2,537 ,, 
Danilewsky. 
Bread crumb . 
3,984 ,, 
j j 
,, ... 
2,537 ,, 
Stohmann. 
Blood fibrin . 
5,772 ,, 
Danilewsky. 
, , ... 
2,525 ,, 
Berthelot and 
I! 
5,637 ,, 
Stohmann. 8 
Petit. 10 
Peptone . . 
4,876 ,, 
Danilewsky. 
,, ... 
2,523 ., 
Rubner. 7 
• • 
5,298 ,, 
Stohmann. 
Uric acid . 
2,741 ,, 
Stohmann. 
Serum albumii 
) 5,917 „ 
Hippuric acid 
5,678 ,, 
,, 
Haemoglobin . 
5,885 ,, 
Ffeces . . . 
4,479 „ 
Rechenberg. 
The above table shows that the different foodstuffs have different 
values as producers of heat, and from these it is possible to calculate 
the physical value of one kind of food in terms of the others. The 
1 Hess, quoted from Rubner {Ztsclir. f. Biol., Miinchen, 1894, Bd. xxx. S. 135). 
2 For further details on such calorimeters, see Miller, "Chemical Physics," p. 338, and 
Watts' "Dictionary of Chemistry," vol. iii. pp. 28, 103; Stohmann, Journ. f. pralct. 
Chem., Leipzig (2), Bd. xix. S. 115 ; Bd. xxxix. S. 503. 
3 Crawford, "On Animal Heat," 1788, 2nd edition, pp. 320, 333, 351 ; Favre and 
Silbermann, Ann. de chim. etphys., Paris, 1842, tome xxxiv. p. 357 ; Frankland, London, 
Edinburgh, and Dublin Phil. Mag., London, 1866, vol. xxxii. p. 182 ; Hermann, Bcr. d. 
deutsch. chem. Gesellsch., Berlin. 186S, S. 18, 84 ; Rubner, Ztsclir. f. Biol., Miinchen, 1885, 
Bd. xxi. S. 357 ; Berthelot, Compt. rend. Acad. d. sc, Paris, 1886, tome cii. pp. 1211, 
1284. 
4 Calorie = the heat required to raise 1 grm. of water 1° C. ; kilo-calorie = 1000 calories = 
heat required to raise 1 kilo of water V C. 
5 Arch.f. d. ges. Physiol., Bonn, 1885, Bd. xxxvi. S. 230. 
6 Journ. f. prakt. Chem., Leipzig, Bd. xliv. S. 336. 
7 Ztschr.f. Biol., Miinchen, 1S93-94, Bd. xxx. S. 88. 
» Ibid., 1895, Bd. xxxi. S. 364. 
9 "Ueber die Verbrennungswarme organischer Substanzen," Leipzig. 1880. 
10 Compt. rend. Acad. d. sc, Paris, 1889, tome cix. p. 759. 
