OXYH^MOGLOBIN. 271 



that only one haemoglobin exists in ox-blood, and that this is probably 

 true for the blood of many other animals. 



Oxyhaemoglobin, which has also been called H.EMATOGLOBULIN or 

 H/EMATOCRYSTALLIN, is a molecular combination of haemoglobin and 

 oxygen. For each molecule of haemoglobin 1 molecule of oxygen is 

 present, as shown by the investigations of HUFNER as well as HUFNER 

 and G AN SSER, and the amount of loosely combined oxygen which is united 

 to 1 gram of haemoglobin (of the ox) has been determined by HUFNER 1 

 as 1.34 cc. (calculated at C. and 760 mm. mercury). 



According to BOHR, the facts are different. He differentiates between four 

 oxyhsemoglobins, according to the quantity of oxygen which they absorb, namely 

 a ~j P~t T- and ^-oxyhaemoglobin, all having the same absorption-spectrum, and 1 

 gram combining with respectively 0.4, 0.8, 1.7, and 2.7 cc. oxygen at the tem- 

 perature of the room and with an oxygen pressure of 150 mm. mercury. The 

 7--oxyhsRmoglobin is the ordinary one obtained by the customary method of 

 preparation. BOHR designates as a-oxyhaemoglobin the crystalline powder 

 obtained by drying 7--oxyhaemoglobin in the air. On dissolving a-oxyhsemo- 

 globin in water it is converted into /?-oxyhsemoglobin without decomposition, and 

 the quantity of iron is increased. On keeping a solution of y-oxyhsemoglobin 

 in a sealed tube it is transformed into ^-oxyhaemoglobin, although the exact 

 conditions under which this change takes place are not known. According to 

 HUFNER 2 these are nothing but mixtures of genuine and partly decomposed 

 haemoglobins. 



The ability of haemoglobin to take up oxygen seems to be a function 

 of the iron it contains, and when this is calculated as about 0.33-0.40 

 per cent, then 1 atom of iron in the haemoglobin corresponds to about 2 

 atoms or 1 molecule of oxygen. By increasing the partial pressure as 

 well as by increasing the quantities of oxygen, the haemoglobin in solu- 

 tion takes up more oxygen, until it is completely saturated, when 1 

 molecule of haemoglobin is combined with 1 molecule of oxygen. Still 

 this reaction is reversible according to the type l(Hb) + l(O 2 )=H(OHb), 

 and with diminished oxygen pressure a dissociation must take place, 

 with the giving up of oxygen and a re-formation of haemoglobin. The 

 equilibrium between oxyhaemoglobin, haemoglobin, and oxygen is deter- 

 mined according to the law of mass-action, and according to the investiga- 

 tions of HUFNER it is possible to calculate the relationship between 

 oxyhaemoglobin (OHb) and haemoglobin (Hb), at every desired partial 

 pressure of the oxygen, by a formula suggested by him. According to 

 BOHR 3 this formula does nojb have sufficient basis and does not correspond 

 to the facts. BOHR found, in opposition to HUFNER' s statements, that 

 with the same oxygen tension the absorption of oxygen by a haemoglobin 

 solution changes with the concentration, and that a dilute solution 



1 Arch. f. (Anat. u.) Physiol., 1901, Suppl. 



2 Arch. f. (Anat. u.) physiol., 1894. 



3 Bohr, Centralbl. f. Physiol., 17, pp. 682 and 688. 



