694 
CHEMISTRY OF RESPIRATION. 
in the lungs, but in earlier works he had admitted that it might be in the 
other organs of the body. 1 
It is now known that the essential seat of respiration is in the tissues and 
not in the blood. The demonstration of this fact is chiefly due to the work of 
Ptiiiger and his pupils. 
Respiratory Changes in Aie. 
Methods for the measurement of respiratory exchange. — The 
simplest and at the same time the earliest method for the measurement 
of respiratory exchange, is the analysis of the air of a bell jar, before 
and after an animal has been confined in it. Such a method was used 
by Black, 2 Priestley, 3 Lavoisier and Laplace, 4 and others. 5 The obvious 
objection to this method is that the products of respiratory exchange 
Fig. 62. — Regnault and Reiset's respiration apparatus. 
accumulate, while the oxygen diminishes, two conditions either of which 
disturbs the normal respiratory exchange, and in time causes the death 
of the animal. 6 Two modifications were introduced by Lavoisier to 
remove these defects : in the one, the carbon dioxide was removed as it 
accumulated, and a fresh supply of oxygen w T as added ; in the other, a 
constant stream of fresh air was passed through the respiration chamber. 
Upon the first of these principles, Regnault and Reiset 7 constructed the 
apparatus w T ith which they made numerous and important experiments 
upon respiratory exchange. The above figure show T s its construction. 
1 "GEuvres," 1862, p. 180. • "Lectures on Chemistry," ed. Rohison, Edinburgh, 1803. 
;i Phil. Trans., London, 1772, vol. lxii. pp. 147, 168. 
4 Hist. Acad. roy. d. sc, Paris, 1780, p. 355. ; "(Euvres de Lavoisier," tome ii. p. 326. 
5 Berthollet, Joum. f. Chem. Physik. u. Mini., Berlin, 1808, Bd. v. S. 388 ; Legallois, 
Journ. f. Chem. «. Phys., Niiniberg, 1817, Bd. xx. S. 113; Valentin, " Die Einflusse der 
Vaguslahmung auf die Lungen und Hautausdunstung," Frankfurt a/M., 1857 ; Arch. f. 
exper. Path. u. Pharmakol., Leipzig, 1876, Bd. v. S. 143. 
6 Bernard, "Lecons sur les etiets des substances toxiques," 1857, p. 130; Friedlander 
and Herter, Ztschr. f. physiol. Chem., Strassburg, Bd. iii. S. 19 ; Stroganow, Arch. f. d. 
ges. Physiol., Bonn, 1876, Bd. xii. S. 18. See also this article, p. 743. 
7 Ann. de chim. etphys., Paris, 1849, Ser. 3, tome xxvi. 
