LIPOCHROME 399 



as established, especially as Ewing finds it to have the same 

 relation to solvents as do the blood-pigments. 



LIPOCHROME 



Iii normal plant and animal tissues occur pigments that are 

 either fats or compounds of fat. In animals they occur nor- 

 mally in the corpus luteum ; in the epithelium of the seminal 

 vesicles, testicles, and epididymis ; in ganglion-cells, especially 

 in the sympathetic nervous tissue; and in fat tissue. Patho- 

 logically, such pigments are found particularly in the muscle- 

 cells in brown atrophy of the heart, and less abundantly in the 

 epithelium of atrophied livers and kidneys (Lubarsch 1 and 

 Sehrt 2 ). All are characterized by staining by such fat stains as 

 sudan III and scarlet R, and usually, but not constantly, by osmic 

 acid ; they are dissolved by the usual fat solvents. It is ques- 

 tionable if all pigments that stain for fat should be considered as 

 true lipochromes, however, for their other reactions are variable. 

 Typical plant lipochromes, including the pigments of Staphyl- 

 ococcus pyogenes aureus and citreus, are colored blue by con- 

 centrated sulphuric acid with formation of small blue crystals 

 of lipocyanin. With iodin-potassium-iodide solution they are 

 colored green. Lipochrome of frog-fat stains blue with the iodin- 

 potassium-iodide solution (Neumann 3 ) ; lipochrome of the cor- 

 pus luteum (called lutein) occasionally gives a faint blue with 

 sulphuric acid or LugoFs solution (Sehrt) ; but the fat-holding 

 pigments of the other tissues mentioned above do not give 

 either of these reactions. Possibly these last are not true lipo- 

 chromes, therefore, but rather pigments chemically or physically 

 combined with fat. Cotte 4 believes that the true lipochromes 

 of plants and animals have a cholesterin base, but the presence 

 of glycerin in plant and bacterial lipochromes can be demon- 

 strated by the acrolein test possibly, therefore, both cholesterin 

 and neutral fats are present. Melanins and pigments derived 

 from hemoglobin do not stain with sudan III and are not sol- 

 uble in ether, etc., and hence can be readily distinguished from 

 the fatty pigments. 



The pigment that causes the peculiar green color characteristic 

 of certain malignant growths, chloromaf was considered by Chiari, 

 Huber, and others as a fatty substance related to or identical 



1 Cent. f. Pathol., 1902 (13), 881. 

 2 Virchow's Arch., 1904 (177), 248. 

 3 Virchow's Arch., 1902 (170), 363. 

 *Compt. Rend. Soc. Biol., 1903 (55), 812. 



5 Literature by Dock, Amer. Jour. Med. Sci., 1893 (106), 152; and Dock 

 and Warthin, Med. News, 1904 (85), 971. 



