CONNECTION BETWEEN BLOOD AND ITS GASES. 767 



oxygen, measured at and 760 mm., which can be absorbed by one 

 volume of water. 



Bohr 1 found that the absorption coefficient of oxygen in a 2 per 

 cent, aqueous solution of haemoglobin at 15 was 0*02249, whereas that 

 for pure water is, according to Winkler, '0341 5, or 50 per cent, greater 

 at the same temperature. 



It has been shown that arterial blood with a temperature of 37 

 contains a large quantity of oxygen, about 22 volumes per cent., an 

 amount which could not be present in simple solution. Further, when 

 the red corpuscles are absent, as in plasma and serum, the amount of 

 oxygen in the fluid is, according to Pfliiger, 2 only 0*26 vols. per cent. 



In the next place, different observers have shown that crystals of 

 haemoglobin can absorb large quantities of oxygen. 



The causes of these differences are various ; the crystals of 

 haemoglobin were prepared in different ways, and it is probable that 

 in some cases methgemoglobin or other products were formed; the 

 amount of moisture varied, and the methods employed for the extraction 

 of the oxygen were different. 



Bohr, 10 however, would explain these differences in another manner, 

 for he maintains that there are at least four different kinds of haemo- 

 globin, -, 13-, y-, and <3-h8emoglobin, which have the same spectrum, but 

 combine with different amounts of oxygen, 0'4, 0*8, 1'7, and 27 c.c. 



1 "Exp. Untersuch. u. d. Sauerstoffaufnahme des Blutfarbsto fifes," Copenhagen, 1885, 

 S. 37. 



2 Arch.f. d. ges. PhysioL, Bonn, 1868, Bd. i. S. 73. 



3 Virchow's Archiv, Bd. xxix. S. 598 ; Med.-chem. Untersuch., 1867, Bd. ii. S. 191. 



4 Hoppe-Seyler, Med.-chem. Untersuch., 1866, Bd. i. S. 117. 



5 Arch.f. d. ges. PhysioL, Bonn, 1871, Bd. iv. S. 454. 



6 CentralU.f. d. med. Wisse.nsch., Berlin, 1866, No. 21. 



7 Ber. d. Jc. sdchs. Gesellsch. d. Wissensch., Leipzig, 1870, Bd. xxii. S. 351. 



8 Ztschr. f. physiol. Chem., Strassburg, 1878, Bd. i. S. 317, 386. 



9 Arch.f. PhysioL, Leipzig, 1894, S. 130. 



10 Skandin. Arch.f. PhysioL, Leipzig, 1892, Bd. iii. S. 47, 69, 76, 101. 



