758 
CHEMISTR Y OF RESPIRATION. 
hydrogen, ox of carbon dioxide, and Vogel, 1 in 1814, and Collard de Martigny, 2 
in 1830, obtained carbon dioxide, but no oxygen, from blood subjected to a 
vacuum. Notwithstanding these observations, the presence of gases in the 
blood was for a long time a subject of controversy. Many physiologists, 
among them Johannes Midler, 3 Schroeder van der Kolk, 4 Gmelin, 5 Mit- 
scherlich, 5 and Tiedemann, 5 maintained that no gas existed in the blood, 
whereas Xasse, 6 Scudamore, 7 Bischoff, 8 and Van Euschut 9 obtained from 
blood carbon dioxide, but no oxygen. John Davy Avas at first 10 unable to 
extract any gas from 
blood, but during a 
further research he 
obtained carbon dioxide 
from both arterial and 
venous blood. 11 
More exact methods 
of observation were in- 
troduced in 1837 by 
Magnus, 1 - who adopted 
and improved, for the 
extraction of the gases, 
the rise of a Torricellian 
vacuum, a method due 
originally to Collard de 
Martigny. The conclu- 
sions to which Magnus 
arrived were that blood 
contained 4-8 volumes 
per cent, carbon dioxide, 
1-3 "5 volumes per cent. 
oxygen, and 0*5-2 
volumes per cent, nitro- 
gen, and that arterial 
bl 1 contained more 
oxygen than did venous 
blood. Fernet, 13 in 1857, 
published the results of 
experiments in which he 
had extracted the gases 
Fig. 69. — Pfluger's Pump; a, blood bulb; b, froth-chamber; f pi blood bv the 
d, drying tube ; e, mercurial gauge ; /;, graduated tube . , "* t 
for collection of gas; I, m, n, and o, bulbs and tubing passage ot a stream ol 
containing mercury. hydrogen, and the aid 
of a vacimm. About 
the same time, Lothar Meyer u developed the method 15 of heating the blood 
or other liquid for the extraction of its gases, and a still further advance was 
1 Journ. f. Chem. u. Phys., Niirnberg. 1814, Bd. xi. S. 399. 
- Journ. de physiol. exper., Paris, 1830, tome x. p. 111. 
3 "Handbuch d. rhysiol.," Bd. i. S. 315. 
4 " Dissertatio sistens sanguinis coagulantis historiam." 
5 Ztschr. f. Physiol., 1833, Bd. v. S. 6. 
6 Loc. cit. 
7 "An Essay on the Blood," London, 1824. 
8 " Commentatio, etc.," Heidelbergse, 1837. 
9 "De respirationis Chymisnio," Trajecti ad Rhenum, 1630. pp. 78, 84, 98, 115, 142. 
10 Phil. Trans., London, 1823, p. 516. 
1] *" Researches," London, 1839, vol. ii. p. 156, et seq. 
12 Ann. d. Phys. u. Chem., Leipzig, 1837, Bd. xl. S. 583 ; 1845, Bd. lxvi. S. 177. 
13 Ann. d. sc. not., Paris, 1857, Ser. 4, Zool., tome viii. p. 125. 
14 "Die Gase des Blutes," Gbttingen, 1857 : Ztschr. f. rat. Med., N.F., Bd. viii. S. 256. 
15 Used originally by H. Davy, Bunsen, and Baumert. 
