758 



CHEMISTR Y OF RESPIRA TION. 



hydrogen, or 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 Miiller, 3 Schroeder van der Kolk, 4 Gmelin, 5 Mit- 

 scherlich, 5 and Tiedemann, 5 maintained that no gas existed in the blood, 

 whereas Nasse, 6 Scudamore, 7 Bischoff, 8 and Van Euschut 9 obtained from 

 blood carbon dioxide, but no oxygen. John Davy was 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, 12 who adopted 

 and improved, for the 

 extraction of the gases, 

 the use 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 

 blood 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; 6, froth-chamber ; f fh }1 -, h & ,, 

 d, drying tube ; e, mercurial gauge ; h, graduated tube 



for collection of gas ; I, m, n, and o, bulbs and tubing passage of a stream of 

 containing mercury. hydrogen, and the aid 



of a vacuum. 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 



I Journ. f. Chem. u. Phys., Niirnberg. 1814, Bd. xi. S. 399. 

 -Journ. dephysiol. exper., Paris, 1830, tome x. p. 111. 



3 "Handbuch d. Physiol.," 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 Chymismo," Trajecti ad Ehenum, 1836. pp. 78, 84, 98, 115, 142. 



10 Phil. Trans., London, 1823, p. 516. 



II "Researches," London, 1839, vol. ii. p. 156, et seq. 



12 Ann. d. Phys. u. Chem., Leipzig, 1837, Bd. xl. S. 583 ; 1845, Bd. Ixvi. S. 177. 



13 Ann. d. sc. not., Paris, 1857, Ser. 4, Zool., tome viii. p. 125. 



14 "Die Gase des Blutes," Gottingen, 1857 : Ztschr. f. rat. Med., N.F., Bd. viii. S. 256. 



15 Used originally by H. Davy, Bunsen, and Baumert. 



