282 THE BLOOD. 



the solid condition as a deep-violet powder which is insoluble in absolute 

 alcohol. In opposition to haemoglobin the haemochromogen combines 

 with oxygen more firmly than with carbon monoxide. The assumption 

 of HOPPE-SEYLER that this compound is a combination of 1 molecule 

 ha3mochromogen and therefore contains 1 molecule carbon monoxide 

 for 1 molecule of iron has been experimentally substantiated by HUFNER 

 and KUSTER and by PREGL. 1 



An alkaline haemochromogen solution has a beautiful cheny-red 

 color. It shows two absorption-bands, first described by STOKES '(spec- 

 trum Plate 6), one of which is dark and whose center corresponds to 

 A = 556.4 between D and E, and a second broader band, less dark, which 

 covers the FRAUNHOFER lines E and b. The middle of this band 

 corresponds to A=526 to 530 according to LEWIN, MIETHE and STENGER. 

 In acid solution haemochromogen shows four bands, which, according 

 to JADERHOLM, 2 depend on a mixture of ha3mochromogen and haemato- 

 porphyrin (see below), this last formed by a partial decomposition 

 resulting from the action of the acid. 



MiLROY, 3 from an alcoholic solution of haematin containing oxalic 

 acid, after driving out the air by means of hydrogen gas, gradually obtained 

 an acid solution of reduced haematin (haemochromogen) by means of 

 zinc dust. This solution showed one absorption-band between D and E. 



Haemochromogen may be obtained as crystals by the action of caustic 

 soda on hemoglobin at 100 C. in the absence of oxygen (HOPPE-SEYLER). 

 By the decomposition of haemoglobin by acids (of course in the absence 

 of air) we obtain haBmochromogen contaminated with a little haematopor- 

 phyrin. An alkaline haBmochromogen solution is easily obtained by the 

 action of a reducing substance (STORES' reduction liquid) on an alkaline 

 haBmatin solution. An ammoniac al solution of haBmatin on reduction 

 with hydrazine yields haBmochromogen very easily. An alcoholic, alkaline 

 hydrazine solution is also recommended by RIEGLER 4 as a reagent for 

 blood-pigments, converting them into haBmochromogen. 



Haematin, also called OXYH^MATIN, is sometimes found in old transu- 

 dates. It is formed by the action of the gastric or pancreatic juices on 

 oxyhaBmoglobin, and is, therefore, also found in the feces after hemorrhage 

 in the intestinal canal, and also after a meat diet and food rich in blood. 

 It is stated that haBmatin may occur in urine after poisoning with arseniu- 

 retted hydrogen. As shown above, the haematin is formed by the decom- 

 position of oxyhaemoglobin, or at least of haemoglobin, in the presence 

 of oxygen. 



1 Hiifner, and Kiister, Arch. f. (Anat. u.) Physiol., 1904, Suppl. Pregl, 1. c. 



2 Nord. Med. Arkiv., 16. 



3 Journ. of Physiol., 32. 



4 Zeitschr. f. anal. Chem., 43. 



