7 i8 
CHEMISTRY 01 RESPIRATION. 
not only to the chemical changes which take place in the food during 
digestion and absorption, but also to the increased glandular and 
muscular activity of the alimentary canal. 1 
Although Lavoisier 2 knew that food greatly increased the respiratory 
exchange, the first experiments of importance in this connection are those 
of Bidder and Schmidt, 3 who made numerous observations upon cats ; 
the results of some of their experiments are given in the preceding table. 
In the case of man and other animals, the influence of food of 
various kinds, and of fasting, has been studied by Pettenkofer and 
Voit, 4 Senator, 5 Henneberg, 6 Leyden and Frankel, 7 Predericq, 8 and 
others ; 9 the general result is that a meal causes an increase in the 
intake of oxygen and the output of carbon dioxide, whereas a day of 
fasting causes a decrease. The average results obtained upon man by 
Pettenkofer and Yoit 10 are as follows : — 
Carbox Dioxide. 
OXTGEN.ll 
Day. Night. 
Day. 
Night, 
1. Fasting — Rest 
Grms. 
403 
Grrus. 
314 
Grms. 
435 
Grms. 
326 
,, Work for nine 
hours out of twelve 
930 
257 
922 
150 
2. Moderate Diet — Rest 
533 
395 
443 
449 
,, ., Work for 
nine hours out of twelve 
856 
353 
795 
211 
Upon the fasting-man Cetti, determinations of the respiratory 
exchange were made by Zuntz and Lehmann, 12 and they found that the 
absorption of oxygen and the discharge of carbon dioxide per kilo. 
of the man's weight quickly reached its minimum, and did not fall 
below this point during the progress of the fast ; in fact there was a 
slight increase. Thus the absorption of oxygen per kilo, and minute 
was 4*65 c.c. on the third to sixth day, and 4*73 c.c. on the ninth to 
eleventh day of the fast. Before the first meal at the end of the 
1 See p. 719. 
2 "(Euvres," tome ii. pp. 695-696. 
3 " Die Verdauungssafte und der Stoffwechsel," Leipzig, 1852, S. 321-362. 
4 Ann. d. Ghem. u. Pharm., 1862-63, Supp. Bd. ii. S. 52-361. 
5 Arch. f. Anat., Physiol., u. wissensch. Med., 1872, S. 1. 
6 Landicirthsch. Versuchsstat., 1S69, S. 306, 409. 
7 Virchows Archiv, 1879, Bd. lxxvi. S. 136. 
8 Arch, de biol., Gand, 1882, tome iii. p. 733. 
9 E. Smith, Phil. Trans., London, 1859, vol. cxlix. p. 715 ; Hanriot and Richet, 
Compt. rend. Acad. d. sc, Paris, 1888, tome cvi. p. 419 ; Zuntz, Fortschr. d. Med., Berlin, 
1S87, Bd. v. S. 1; Meissel, Strohmer, and Lorenz, Ztschr. f. Biol., Miinchen, 1886, Bd. 
xxii.'s. 63 ; Bceck and Bauer, ibid., 1874, Bd. x. S. 336 ; Geppert, Arch. f. exper. Path, 
u. Pharmakol., Leipzig, 1887, Bd. xxii. S. 366; Hanriot and Richet. Ann. de chim. el 
phys., Paris, 1891, Ser. 6, tome xxii. p. 495 ; Marcet, Proc. Key. Soc. London, 1892. 
vol. 1. p. 58 ; 1893, vol. Iii. p. 213 ; Rubner, Beitr. z. Physiol. Carl Ludwig z. s. 70 
Geburtst., Leipzig, 1887, S. 259 ; Johansson, Landergren, Sonden, and Tigerstedt, Skandin. 
Arch. f. Physiol?, Leipzig, 1896, Bd. vii. S. 29. 
10 Ztschr. f. Biol., Munchen, 1866, Bd. ii. S. 459. 
11 For criticism of the determination of oxygen, see p. 696. 
12 Bed. klin. Wduxschr., 1887, S. 428. 
