482 PATHOLOGICAL PIGMENTATION 



to form new hemoglobin molecules. This hj^pothesis is merely ten- 

 tative, but it affords a useful "working hypothesis" for the considera- 

 tion of many phases of pigment metabolism. 



In the decomposition of hemoglobin the first step is the splitting 

 of the globin (which does not form pigments) from the hematin, from 

 which many pigments may be derived. 



Hematin. — The formula given for this substance by Nencki is 

 C32H32N4Fe04 while Hoppe-Seyler proposed the formula C34H34 

 N4Fe05, although it is not certain that the hematin of all animals is 

 the same. It is found frequently as an amorphous, dark-brown or 

 bluish-black substance, in large, old extravasations of blood, but sel- 

 dom in small hemorrhages. As a pathological pigment hematin is 

 by no means so frequently found as its derivatives. Schumm^^ ob- 

 served a patient with chromium poisoning w^ho showed for several 

 days abundant hematin free in the blood. He has also found it in 

 malaria, pernicious anemia, congenital hematoporphj^ria, and gener- 

 ally with acute toxic hemolysis, including patients infected with B. 

 eniphysematosus, when the hematin may be accompanied by me+he- 

 moglobin without a corresponding urinary excretion of these pigments. 

 Feigl found hematinemia in many cases of poisoning with the war gases. "^ 

 Brown" found that solutions of hematin cause chills and fever, and 

 suggests that his pigment may be at least partially responsible for 

 the symptoms of malaria. '^^ Hematin has been beheved to spht up 

 gradually into an iron-free pigment {hematoidin) and an iron-contain- 

 ing pigment {hemosiderin). This change may be represented by the 

 following equation, according to Nencki and Sieber:^^ 



C32H32N404Fe + 2H2O = 2C,6H,8N203 + Fe. 

 (hematin) (hematoidin) 



However, finding that the pigment in the malarial spleen is hematin, 

 Brown^" suggests that hematin cannot well be an intermediary prod- 

 uct in hemoglobin disintegration, since this malarial pigment persists 

 a very long time in the tissues without change. He has made other 

 observations that led him to conclude that hematin is not an inter- 

 mediary substance between hemoglobin and hemosiderin, but that 

 when once formed it is destroyed very slowly, by oxidation rather than 

 hydrolysis. Injected into rabbits it produces vascular lesions in the 

 kidneys**' and in large doses causes a marked fall in blood pressure. *- 

 Hematoidin may be found in old, large extravasations, as orange- 



" Zeit. physiol. Chem., 1912 (80), 1; 1913 (87), 171; 1916 (97), 32. 

 '« Biochem. Zeit., 1919 (93), 119. 

 " Jour. Exper. Med., 1912 (15), 580; 1913 (18), 96. 



'8 Disputed by Butterfield and Benedict, Proc. Soc. Exp. Biol., 1914 (11),''80. 

 "Arch. exp. Path. u. Pharm., 1888 (24), 440; Brugsch and Vo.slumoto, Zeit. 

 exp. Path., 1911 (8), 639. 



"ojour. Exper. Med., 1911 (13), 290; 1911 (14), 612. 



«' Arch. Int. Med., 1913 (12), 315. 



" Brown and Loevenhart, Jour. Exp. Med., 1913 (IS), 107. 



