SEATS OF HEAT PRODUCTION. 839 
following are Borne of his results, and also those obtained recently by 
Rosenthal : ' — 
Crawford. 
Rosenthal. 
Lean beef . 
= 0-740 
Compact bone 
= 0-300 
Hide of an ox with the hair 
= 0-787 
Spongy bone 
= 0-710 
Lungs of a sheep . 
= 0-769 
Fat .... 
= 0-712 
Fresh milk of a cow- 
= 0-999 
Voluntary muscle 
= 0-825 
Arterial blood of a dog . 
= 1-030 
Defibrinated blood 
= 0-927 
Venous blood 
= 0-8928 
It is to be noted that Davy, 2 Hillersohn, and Stein Bernstein 3 were 
unable to find any marked difference between the specific heats of 
arterial and venous blood. Recently Hale White i has made an in- 
genious attempt to obtain the specific heat of a living warm-blooded 
animal by experimenting upon a hibernating dormouse. His results 
vary between 0'812 and 1*18, but they are only approximately accurate, 
for the dormouse, even during hibernation, produces a small amount of 
heat. 
Since all the tissues of the body contain a quantity of water, the mean 
specific heat must be near unity, probably about 0'83. 
The Seats of Heat Production. 
The work of Mayow (1674), Black (1757), Priestley (1772), 
Lavoisier (1777), and Crawford (1779) 5 led to the conclusion that 
animal heat was due to a process of combustion occurring in the body, 
but concerning the chief seat of this combustion there was no unanimous 
opinion. Mayow considered that the oxidation took place in the tissues 
all over the 1 tody : Crawfi ncl held that the heat was set free chiefly in 
the capillaries of the body, owing, as he thought, to a difference in the 
specific heat of arterial and venous blood ; Lavoisier was at first un- 
decided, and considered that the heat arose in the lungs, and possibly in 
other parts of the body, but finally he maintained that the lungs were 
the chief seat of combustion. The theory of Lavoisier was contested by 
Lagrange, 6 who maintained that if all the heat of the body were pro- 
duced in the lungs, the tissues of that organ would be destroyed by so 
high a temperature. This objection was for long held to be fatal to 
Lavoisier's theory, until Berthelot, 7 by a careful calculation, showed that, 
granting all the heat to be formed in the lungs, the temperature of those 
parts would not be raised more than a minute fraction of a degree, 
owing to the great volume of air and blood in the lungs and the rapidity 
of the circulation, whereby the heat would be quickly distributed. 
Moreover, Berthelot has shown by experiment that a small amount of 
heat is formed in the lungs by the combination of oxygen with 
1 Arch. f. Physiol., Leipzig, 1878, S. 215. 
- "Researches,"' London, 1839. 
3 Arch. f. Physiol., Leipzig, 1896, S. 249. 
4 Jour a. Physiol., Cambridge and London. 1892, vol. xiii. p. 789; Croonian Lectures, 
Lancet, London, June 19, 1897 ; Brit. Med. Journ., London, 1897, vol. i. p. 1653. 
5 Mayow, "Tractatus Quinque," 1674 ; Black, "Lectures on Chemistry," edited by 
Eobison, Edinburgh, 1S03 ; Priestley, Phil. Trans., London, 1772, vol. lxii. p. 147 ; 
Crawford, " De Galore Animali," 1779 ; "On Animal Heat," 2nd edition, 1788 ; Lavoisier, 
Brit. Acad. roy. d. sc, Paris, 1777. 
6 Hasseufratz, Ann. de chirn., Paris, 1791, tome ix. p. 275. 
7 Compt. rend. Acad. d. sc, Paris, 1889, tome cix. p. 776. 
