BLOOD PIGMENTS 483 



colored or red rhombic plates, first described by Virchow. Some- 

 times, however, hematoidin occurs in the form of yellowish granular 

 masses, and it may be associated with lipoids; it is also found irt 

 crystalline form in icterus (Dunzelt).^' It seems to be nearly or 

 quite identical with the bile-pigment, bilirubin, and it is probably the 

 source of this substance under normal conditions. When formed in 

 excessive amounts, either through increased destruction of corpuscles 

 in the vessels or in extravasations, the amount of bile-pigment is in- 

 creased (see "Icterus"). Possibly some of the hematoidin becomes 

 transformed (Urectly into urobilin, and is then eliminated in the urine. 



Hemosiderin'*'' is relatively insoluble, and, therefore, is more 

 slowly removed when formed in hemorrhages, and more abundantly 

 deposited in the tissues when formed after excessive hemolysis. In 

 acute hemolytic anemia a third of the total iron of the blood may be 

 deposited in the liver, spleen and kidneys within 24 hours. ^'^ In 

 infarcts hemosiderin soon disappears (Schmidt), ^"^ presumably because 

 dissolved by the acids formed during autolysis. According to Neu- 

 mann, hemosiderin is produced only under the influence of living cells 

 and in the presence of oxygen, while hematoidin arises independent 

 of cellular activity;^^ but Brown^^ has found that hemosiderin can be 

 formed during autolysis of the liver, especially when air is present, 

 and therefore probably by an oxidizing enzyme. He suggests that in 

 hemosiderin the pigment is still hematoidin, and that the formation 

 of^hemosiderin takes place in the nuclei, the hemosiderin being made 

 directly from hemoglobin without the intervention of hematin. It 

 may also be formed from the iron-containing protein of the cells during 

 autolysis, independent of hemoglobin. ^^ Milner^" considers that, 

 under similar conditions, an iron-containing pigment is also formed, 

 which differs from hemosiderin in having the iron so combined that 

 it cannot react with the usual reagents; this pigment may later change 

 into hemosiderin. Up to the present time we do not know the chemi- 

 cal nature of hemosiderin, nor its exact fate in the body, but it is 

 probably utilized in the manufacture of new hemoglobin, for it is 

 known that the iron liberated when hematin is broken up in the body 

 under experimental conditions is deposited and not eliminated (Mor- 

 ishima).^^ 



Unstained hemosiderin generally appears in the form of brown 



*^ Cent. f. Path. 1909 (20) 966. 



8-« See Neumann! Virchow's Arch., 1888 (111), 25; 1900 (161), 422; 1904 (177), 

 401; also Arnold, ibid., 1900 (161), 284; Leupold, Beitr. path. Anat., 1914 (59), 501. 



s^Muir and Dunn, .Jour. Path, and Bact., 1915 (19), 417. 



86 Verh. Deut. Path. Gesell., 1908 (12), 271. 



8^ The accumulation of iron in the liver which follows poisoning with hemolytic 

 agents, is not prevented or diminished bv preliminary removal of the spleen 

 (Meinertz, Zeit. exp. Path. u. Ther., 1906 (2), 602). 



S8 Jour. Exper. Med., 1910 (12), 623. 



83 Sprunt et al, Jour. Exp. Med., 1912 (16), 607. 



90 Virchow's Arch., 1903 (174), 475. 



»i Arch. exp. Path. u. Pharm., 1898 (41), 291. 



