PRODUCTION OF HEAT IN MUSCLE. 
841 
Similar results have lii'cn obtained by Rubner l in limbs through which an 
artificial circulation of blood was maintained. 
Although, as Hermann- has shown, some of the carbon dioxide may arise 
from the action of bacteria, yet these experiments show that even excised 
muscle is the seat of an energetic metabolism and of heat production. Tissot 3 has 
proved that the absorption of oxygen and the discharge of carbon dioxide occur 
in an excised muscle, even when every precaution is taken to maintain asepsis. 
The results of Minot's 4 experiments upon the production of carbon dioxide in 
resting and active muscle are opposed to those obtained by Paid Bert and 
Regnard, but his method has been shown by Zuntz 5 to be open to serious 
objections. 
The subject of respiration in muscle will be discussed more fully in other 
parts of this work, 6 here it is only necessary to point out that the respiratory 
exchange of a muscle, even during apparent rest, is very marked, and becomes 
enormously increased during activity. This is well shown by the experiments 
of Sczelkow," von Frey, 8 Chauveau and Kaufmann, 9 Hill and Xabarro. 10 
Difference between" Venous and Arterial Blood. 
Muscle at Rest. 
Muscle Active. 
Sczelkow . . . -i 
Chauveau and Kaufmami - 
Hill and Nabarro . . - 
CO, 
0, 
CO, 
0, 
co 2 
0, 
+ 671 
-9-00 
+ 8-70 
-11-40 
+ 8-76 
-12-92 
+ 32-37 
-36-78 
+ 30-60 
-40-95 
Tonic. Clonic. 
+ 41-70 +57-99 
-41-25 -37-89 
The muscles during apparent rest are in a state of tone, and are the seat of 
an energetic combustion, and therefore of heat production. 
Further evidence of the important part played by the muscles in the 
production of heat is found in the fact that any cause which suspends 
the activity of the muscles, or more correctly the neuro-muscular 
system, lowers the temperature of the body. Curari causes muscular 
paralysis and a fall in the temperature of the body ; n the respiratory 
exchange is greatly diminished, even if the animal's temperature is 
1 Arch. f. Physiol., Leipzig, 1885, S. 38; this Text-book, article "Chemistry of 
Respiration." 
- " Untersuch. u. d. Stofl'wechscl der Muskeln," Berlin, 1867, S. 37. 
3 Arch. dephysiol. norm, etpaih., Paris, 1894, tome xxvi. p. 838 ; 1895, tome xxvii. 
4 " Die Bilduug der COo iimerhalb des ruhenden und erregten Muskeln." 
3 Hermann's " Handbuch," Bd. iv. Th. 2, S. 96. 
6 See articles on " Chemistry of Respiration" and on "Metabolism," this Text-book, 
vol. i. 
7 Sitzwngsb. d. Je. Akad. d. Wissensch., Wien, 1862, Bd. xlv. 
8 Arch. f. Physiol., Leipzig, 18S5, S. 533. 
9 Compt. rend. Acad. d. sc, Paris, 1886, tome ciii. pp. 974, 1057, 1153. 
10 Jour a. Physiol., Cambridge and London, 1895, vol. xviii. p. 218. 
11 Tscheschichin, Arch. f. Anat. Physiol, u. ivissensch. Med., 1866, S. 159. During 
the convulsions which are at first caused by curari the temperature rises ; Bernard, 
" Lecons sur la chaleur animale," 1876, p. 157 ; Velten, Arch. f. d. yes. Physiol., Bonn, 
1880', Bd. xxi. S. 361. 
