OXYH^MOGLOBIN. 27 1 



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 GANSSER, and the amount of loosely combined oxygen which is united 

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

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



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

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

 a "j -> T- an d #-oxyhsemoglobin, 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 

 f-oxyhsemoglobin is the ordinary one obtained by the customary method of 

 preparation. BOHR designates as a-oxyhaemoglobin the crystalline powder 

 obtained by drying r-oxyhaemoglobin in the air. On dissolving a-oxyhaemo- 

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

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

 in a sealed tube it is transformed into d-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)-f-l(O2)<=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 not 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. Pbysiol., 17, pp. 682 and 688. 



