486 PATHOLOGICAL PIGMENTATION 



phenomenon in and about the abdominal cavity, and in the ordinary 

 postmortem discoloration both the liberation of the iron from its 

 firm organic combination, and the production of hydrogen sulphide, 

 are the work of bacteria. Pseudomelanosis may occur intra vitam, 

 particularly in the margins of infected areas, and it may also be ob- 

 served in the intestines, liver and spleen, and about the peritoneum, 

 in bodies examined immediately after death, before any evident post- 

 mortem decomposition has set in. This seems to depend upon the 

 previous intra vitam formation of hemosiderin, which is then combined 

 by sulphur liberated from tissue proteins through bacterial action.^ 



Methemoglobin. — If hydrogen sulphide acts upon hemoglobin 

 that has not been decomposed, a greenish compound of sidphur- 

 methemoglobin is formed (Harnack^), which is the cause of the greenish 

 color seen in the abdominal walls and along the vessels of cadavers. 

 This union of hemoglobin and hydrogen sulphide occurs only when 

 oxygen is present (oxyhemoglobin). The sulphur-hemoglobin com- 

 pound is readily decomposed by weak acids, even by CO2, with the 

 formation of methemoglobin, which in turn readily becomes decomposed 

 to form hematin. During life sulphemoglobin may form in the cir- 

 culating blood, the sulphur presumably coming from intestinal putre- 

 faction, and hence the condition is called "enterogenous cyanosis," 

 which term also covers methemoglobinemia produced by nitrites formed 

 in the intestines. '^ The latter condition is also present in poisoning 

 by phenacetin,^ aniline and acetanilid, and related pigments appear 

 in the blood in poisoning with chlorates and nitrobenzol. Pneu- 

 mococci and Streptococcus viridans, as well as some other bacteria, 

 may produce methemoglobin.^ In infections with B. em-physem.atosus , 

 Schumm found this pigment free in the blood. Van den Bergh^° 

 has found sulphemoglobinemia in puerperal sepsis, and probably these 

 pigments could be found in other conditions if sought. 



Hemof uscin is the name given by von Recklinghausen to the 

 brownish pigment found in involuntary muscle-fibers, particularly in 

 the wall of the intestine. It does not react for iron, and is insoluble 

 in alcohol, ether, chloroform, or acids; therefore it is not a lipochrome. 

 It is bleached by H2O2, and is often found associated with hemosiderin 

 which is not bleached. Von Recklinghausen, and also Goebel,^' 

 ascribe this pigment to an alteration of hemoglobin which enters the 

 cells in dissolved form, but Rosenfeld,^- who has subnutted the mater- 



' Ernst, Virchow's Arch., 1898 (152), 418. Literature. 



« Zeit. physiol. Chem., 1899 (2G), 558. 



' West and Clarke, Lancet, Feb. 2, 1907; Davis, ibid., Oct. 26, 1912; Gibson 

 Quart. Jour.Med., 1907 (1), 29; Long and Spriggs, /6/(/., 1918 (IH, 102; .Tamieson, 

 ibid., 1919 (12), 81. 



8 See Heuhner, Arch. exp. Path., 1913 (72), 241. 



9 Cole, Jour. Kxp. Med., 1914 (20), 303; Blake ibid., 1916 (24), 315; Schumm, 

 Zeit. physiol. (Miem., 1913 (87), 171. 



"• Nederl. Tijd. Geneesk., 1918 (1), 1774. 



" Virchow's Arch., 1894 (136), 482. 



" Arch. exj). Path. u. Pharin., 1900 (45), 46. 



