OXYH^EMOGLOBIN. 281 



3-10 per cent for the different oxyhsemoglobins. When completely 

 dried at a low temperature over sulphuric acid the crystals may be 

 heated to 110-115 C. without decomposition. At higher temperatures, 

 somewhat above 160 C., they decompose, giving an odor of burned horn, 

 and leave, after complete combustion, an ash consisting of oxide of 

 iron. The oxyhsemoglobin crystals from difficultly crystallizable blood, 

 for example from such as ox's, human, and pig's blood, are easily 

 soluble in water. The oxyhsemoglobins from easily crystallizable 

 blood, as from that of the horse, dog, squirrel, and guinea-pig, are soluble 

 with difficulty in the order above given. The oxyhsemoglobin dissolves 

 more easily in a very dilute solution of alkali carbonate than in pure water, 

 and this solution may be kept. The presence of a little too much alkali 

 causes the oxyhaemoglobin to decompose quickly. The crystals are 

 insoluble in absolute alcohol without decolorization. According to 

 NENCKI 1 it is converted into an isomeric or polymeric modification, 

 called by him parahoemoglobin. Oxyhsemoglobin is insoluble in ether, 

 chloroform, benzene, and carbon disulphide. 



A solution of oxyhsemoglobin in water is precipitated by many metallic 

 salts, but is not precipitated by sugar of lead or basic lead acetate. On 

 heating the watery solution it decomposes at about 70 C., and splits 

 off protein and hsematin when sufficiently heated. It is also readily 

 decomposed by acids, alkalies, and many metallic salts. It gives the 

 ordinary reactions for proteins with those protein reagents which first 

 decompose the oxyhsemoglobin with the splitting off of protein. Oxy- 

 hsemoglobin, like the other blood-pigments, has a direct oxidizing action 

 upon tincture of guaiacum. It has, on the other hand, like all blood- 

 pigments containing iron, the property of an " ozone transmitter " in 

 that it turns tincture of guaiacum blue in the presence of reagents con- 

 taining peroxide, such as old turpentine. 



A sufficiently dilute solution of oxyhsemoglobin or arterial blood 

 shows a spectrum with two absorption-bands between the FRAUN- 

 HOFER lines D and E (spectrum Plate 1). The one band, a, which is nar- 

 rower but darker and sharper, lies on the line D; the other, broader, 

 less defined and less dark band, /3, lies at E. The middle of the first 

 band corresponds to a wave-length X = 579 and the second X = 542. On 

 dilution the band |8 first disappears. By increased concentration of the 

 solution the two bands become broader, the space between them smaller 

 or entirely obliterated, and at the same time the blue and violet part 

 of the spectrum is darkened. Besides these two bands we can also observe 



1 Nencki and Sieber, Ber. d. d. chem. Gesellsch., 18. According to Kriiger (see 

 Biochem. Centralbl., I, 40, 463) haemoglobin is somewhat changed by alcohol as well 

 as by chloroform. 



