x HAEMOGLOBIN 485 



v. Zeynek l and Hiifner 2 obtained in the best experiments about 13 per 

 cent less oxygen than was present in the oxyhsemoglobin solutions 

 Avhen judged by the spectro-photometer. Apart from the doubts as to 

 the reliability of the data on which Hiifner has based his spectro- 

 photometric calculation (see above p. 482), Haldane points out that the 

 only factors liable to give too low figures by the ferricyanide method 

 are, firstly, incomplete laking of blood, as ferricyanide cannot act on 

 the haemoglobin in the corpuscles, and, secondly, the presence of 

 bacteria. Miiller 3 fully concurs with Haldane that the ferricyanide 

 method gives the same results as does the blood-pump, but draws 

 attention to the fact that bacteria are not the only agents by means 

 of which blood, which has left the arteries, may after a time show a 

 diminution in the amount of removable oxygen, for if the analyses of 

 Bohr, 4 and even those of Hiifner and v. Zeynek, are examined in an 

 unbiassed manner, there is no doubt that many samples of blood, 

 after having been kept for some time aseptically, do not give the 

 maximal oxygen capacity of 1*34 ccm. per gramme of haemoglobin, 

 and he accounts for the loss of oxygen by assuming that the blood of 

 some individuals contains " easily oxidisable substances, which com- 

 bine with the loosely bound oxygen of kept blood or with the 

 oxygen which is set free by ferricyanide, while the oxygen is in statu 

 nascendi." He thus explains the differences obtained occasionally on 

 examining kept blood by the ferricyanide method as due to the auto- 

 consumption of the oxygen by the blood. Certain individuals do not 

 seem to possess the radical which absorbs the oxygen, and in this case 

 the ferricyanide gives the same results with freshly drawn and with 

 kept blood, if bacterial action be excluded. The chemical interaction 

 between blood and potassium ferricyanide is discussed on p. 492. 



Normal oxyhsemoglobin is very readily dissociated, while haemo- 

 globin crystals, in the preparation of which alcohol was used, do 

 not dissociate so readily. This was first shown by Loewy, 5 and then 

 confirmed by Hiifner. 6 That the dissociation of oxy haemoglobin 

 is greater at higher temperatures has been shown by Hiifner, 6 who 

 has also given tables to show the inter-relationship of the oxygen 

 tension and the percentage saturation of haemoglobin. As his tables 

 .are based on calculation, and not on actual, observation, they have 



1 v. Zeynek, Arch. f. (Anat. u.) Physiol. 1899, p. 460. 



2 Hiifner, ibid. 1899, p. 491. 



3 Franz Miiller, PJlilger's Arch. 103. 541 (1904). 



4 Bohr, Skand. Arch. 3. 101J1891). 



5 A. Loewy, Zentralbl. f. Physiol. 13. 449 (1889). 



6 G. Hiifner, Arch. f. (Anat. u.) Physiol. 1890, p. 28 ; 1901, Suppl. p. 187 ; 

 Zeitschr. f. physiol. Chem. IQ. 218 (1886). 



