7 1 2 CHEMISTR Y OF RESPIRA TION. 



made upon the influence of external temperature upon the respiratory 

 exchange of warm-blooded animals. The general result of this work is 

 that the intake of oxygen and the output of carbon dioxide increase 

 with a fall and decrease with a rise of external temperature. This is 

 shown by the examples, which have been taken from the results obtained 

 by different observers, and are given in the preceding table. 



It appears that, when the external temperature is raised to a point 

 about 30, the respiratory exchange shows an increase above the amount 

 observed at a temperature of 20. Thus Voit l found in the case of a 

 man, that the output of carbon dioxide was increased by a fall of 9 or 

 10 below the average temperature 14 15, and also increased by a rise 

 of 15 or 16 above that point; the augmentation in the discharge of 

 carbon dioxide was respectively 36 per cent, and 10 per cent, above that 

 given off at 14-15. A similar result was obtained by Page, 2 who 

 found that at a temperature of 25 9 the discharge of carbon dioxide by a 

 dog was at a minimum ; a fall or rise of 10 below that point produced a 

 mean increase of 31 per cent, and 51 per cent, respectively. 3 Unfortun- 

 ately Voit gives no details as to the temperature of the man during 

 the experiments, but in one or two cases Page notes that the tempera- 

 ture of the dog was raised above the normal by exposure to the 

 warm air. 



The earliest experiments upon the influence of external temperature 

 on the respiratory exchange of man were made by Lavoisier and Seguin, 4 

 who found that a man at rest absorbed in an hour 34'49 grnis. of 

 oxygen when the air was 32'5, but 38'31 grms. when the temperature 

 was 15. Since that time many observations 5 have been made upon 

 man and the effect of external temperature on his respiratory exchange, 

 and of these the most important are those made by Lowy. 6 The 

 general result drawn from his experiments is that the effect of external 

 cold varies in different men. Out of fifty-five experiments, the oxygen 

 absorbed was increased above 5 per cent, in twenty-six cases, unaltered in 

 twenty, and diminished in nine cases. In these experiments, in which the 

 metabolism was increased, for the variations in the output of carbon 

 dioxide followed those in the absorption of oxygen, the heights to which 

 it was raised varied between 5 and 90 '8 per cent, above the normal. A 

 point worthy of note is that the greatest increase in the respiratory 

 exchange was observed in the men who shivered or moved when they 

 felt cold, and that the respiratory exchange remained unaltered or 

 decreased in the men who, notwithstanding the sensation of cold, 

 remained quiet, and by an effort of the will suppressed any tendency to 

 move or shiver. Lowy concludes that the only involuntary regulator 

 of temperature in a man exposed to moderate cold is the skin. It must 

 be pointed out, however, that increased muscular activity in a man who 



1 Ztschr.f. Biol., Mtinchen, 1878, Bd. xiv. S. 80. 



2 Journ. Physiol., Cambridge and London, 1879-80, vol. ii. p. 228. 



3 See also Rubner, " Biologische Gesetze," Universitats-programm, Marburg, 1887; 

 abstract in Centralbl. f. PhysioL, Leipzig u. Wien, 1887, S. 700. 



4 ".(Euvres de Lavoisier'/' tome ii. .pp. 688, 704; Hist. Acad. roy. cL sc., Paris, 1789, 

 p. 575. See also Rep. Brit. Ass. Adv. He., London, 1871, p. 189. 



5 Vierordt, "Physiol. des Athmens," 1845; E. Smith, Phil. Trans., London, 1859, 

 vol. cxlix., p. 681 ; Speck, Schrift. d. Gesellsch. z. Beford. d. ges. Naturw. zu Marburg, 

 1871, Bd. x. ; Liebermeister, Deutsches Arch. f. Win. Med., Leipzig, 1872, Bd. x. S. 89, 

 420 ; Lehmann, Virchow's Archiv, 1873, Bd. Iviii. S. 92. Johansson, Skandin. Arch. f. 

 PhysioL, Leipzig, 1897, Bd. vii. S. 123. 



6 Arch.f. d. gcs. Physiol. , Bonn, 1890, Bd. xlvi. S. 189. 



