MEASURE OE HEAT PRODUCTION. 
847 
Heat Produ I. 
Animal. 
132,000 cal. per hour. 
140,000 ,, 
99,000 ,, 
21,000 eal. per hour. 
12,630 ,, 
10,900 ,, 
2,f>00 cal. per hour and 
per kilo. 
Ailult man. 
5,920 cal. per hour and 
per kilo. 
6,000 
Dog weighing 
5350— 5450 tmns. 
Do£s. 
Pigeon. 
Remarks. 
Observer. 
A1 rest. 
Partial calorimeter 
used. 
One hour after food. 
Twenty-six hours 
after food. 
About forty-nine > 
hours after food. 
About thirty- six 
hours after food. 
Mean of experiments 
on six dogs. 
Normal. 
After removal of 
cerebral hemi- 
spheres. 
Scharling. 1 
Hirn.- 
Leyden. 3 
Senator. 4 
Corin and Van 
Beneden. 5 
The respiratory exchange as a measure of heat production. — 
The heat of the body has been shown to be due to processes of com- 
bustion occurring in the tissues. The respiratory exchange is a measure 
of this combustion, and hence a determination of the intake of oxygen 
and the output of carbon dioxide is a measure, although not a perfectly 
accurate one, of the heat produced. There is, however, one source of 
inaccuracy in this method ; a determination of the respiratory exchange 
during a limited time is not an exact indication of the combustion occur- 
ring during that time, for we know that oxygen may be taken up and 
stored in the body for a considerable period, and carbon dioxide may 1 ie 
given off by the breaking up of previous combinations ; in fact, may still 
be evolved when the tissues are receiving no free oxygen. Nevertheless, 
consecutive determinations of the respiratory exchange for long periods, 
and careful observations of the animal's temperature, form a most valu- 
able method for the study of the regulation of temperature by heat 
production, especially since calorimetric experiments are more tedious, 
difficult, and more open to accidental sources of error. 
In the case of warm-blooded animals, a fall in external tempera- 
ture increases, a rise diminishes the intake of oxygen and the out- 
put of carbon dioxide. Crawford 6 and Lavoisier" came to this 
conclusion not only on theoretical grounds, because they believed that 
animal heat was due to combustion, but from the results of direct 
experiment. 
1 Journ. f. prakt. Chem., Leipzig, 1849, BJ. xlviii. S. 435. 
2 " Recherches sur Fequivalent niecanique de la ehaleur," Paris, 1858; "Exposition 
analytique et expe'rimentale de la th£orie niecanique de la ehaleur,'" Paris, 1875, 3e edition, 
tome i. p. 27. 
3 Beutsches Arch. f. Tclin. Med.. Leipzig, 1869, Bd. v. S. 273. 
4 GemtraZbl.f. d. med. ll'lssensch. , Berlin, 1871 ; Arc/*./. Anat., Physiol, v.. iclssensch. 
Med., 1872, S. i. ; 1874, S. 18; " Untersnch. ueber den fieberhaften Process und seine 
Behandlung," Berlin, 1873, S. 30. 
3 Arch, de biol., Gand, 1887, tome vii. p. 276. 
6 " Experiments and Observations on Animal Heat," 1788, 2nd edition. 
7 Hist. Acad. roy. d. sc, Paris, 1780, p. 407. 
