7 i8 



CHEMISTR Y Of 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 : 



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 473 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 "CEuvres," tome ii. pp. 695-696. 



3 " Die Verdauungssafte und der Stoffwechsel, " Leipzig, 1852, S. 321-362. 



4 Ann. d. Chem. u. Pharm., 1862-63, Supp. Bd. ii. S. 52-361. 



5 Arch. f. Anat., PhysioL, u. wissensch. Med., 1872, S. 1. 



6 Landwirthsch. Versuchsstat., 1869, S. 306, 409. 



7 Tirchow's Archiv, 1879, Bd. Ixxvi. 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, 

 1887, Bd. v. S. 1 ; Meissel, Strohmer, and Lorenz, Ztschr. f. BioL, Mlinchen, 1886, Bd. 

 xxii. S. 63 ; Bceck and Bauer, ibid., 1874, Bd. x. S. 336 ; Geppert, Arch. f. exper. Path, 

 u. PharmaJcoL, Leipzig, 1887, Bd. xxii. S. 366; Hanriot and Richet, Ann. de chim. et 

 phys., Paris, 1891, Ser. 6, tome xxii. p. 495 ; Marcet, Proc. Pioy. 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 Tigers tedt, 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 BerL klin. Wchnschr., 1887, S. 428. 



