408 RETROGRESSIVE CHANGES 



to Anitschkow and Chalatow {loc. cit). the feeding of foods rich in 

 cholesterol may cause the appearance in the liver of great quantities 

 of anisotropic droplets, lipoid deposits in the aorta, enlargement of the 

 adrenal cortex, and the presence in practically all tissues of semifluid, 

 doubly refracting crystalline structures (cholesterol steatosis).^- 



In cells undergoing autolysis the fat-like "myehn" droplets which 

 appear, differ from the above in not being anisotropic, but are un- 

 doubtedly closely related to them in composition. These "myelin" 

 droplets are also found in cells showing cloudy swelling, presumably 

 representing cell lipoids set free through changes in the cell proteins. 

 They are. characterized by staining with osmic acid but not by sudan 

 III, which shows them not to be simple fats nor yet lipoids, but they 

 are undoubtedly precursors of true fatty degeneration;^^ they prob- 

 ably consist chiefly of lecithin, with more or less free fatt}' acids and 

 relatively little cholesterol (Aschoff). 



It is possible to distinguish the lipoids of cells, whether normal or 

 pathological, from the neutral fats by means of Ciaccio's method.^* 

 This consists in a preliminary treatment with bichromate, which ren- 

 ders the lipoids insoluble; the tissues can then be hardened and im- 

 bedded by the usual methods which remove the unchromated fats, 

 leaving the lipoids stainable by sudan III. By tliis method BelP° 

 has been able to stain the lipoids in the normal kidney and other tis- 

 sues, in sufficient amount to account for all the so-called "masked 

 fat," which thus seems to be, as also indicated by chemical evidence, 

 largely lipoidal. 



Jastrowitz^^ has studied the relation of lipoids to fats in the fatty 

 changes produced by various means, and finds that in severe fatty 

 changes with much transported fats there may be little change in the 

 lipoids; with blood poisons which cause little increase in total fats, 

 the lipoid content of both blood and organs may be high; usually the 

 phosphatid content is unchanged or slightly increased, but it may be 

 decreased. The proportion of cholesterol to neutral fats is usually 

 within normal limits in tissues showing fatty changes.^' The mito- 

 chondria seem to be compounds of phospholipins with proteins, and 

 these agglutinate and form fathke droplets in phosphorus poison- 

 ing. 38 presumably they play an important role in fatty metamor- 

 phosis. Cells in tissue cultures, however, may take up fat droplets 

 from the surrounding medium {i. e., fatty infiltration), without any 

 association with or changes in the mito-chondria.^' 



"See also Anitschkow, Deut. med. Woch., 1913 (39), 741; Wesselkin, Vir- 

 chow's Arch., 1913 (212), 225; Rubinstein, Compt. Rend. Soc. Biol., 1917 (80), 

 191. 



33 Hess and Saxl, Virchow's Arch., 1910 (202), 149. 



3^ Cent. f. Path., 1909 (20), 771; Arch. f. Zellf., 1910 (5), 235. 



36 Jour. Med. Res., 1911 (24), 539. 



38 Zeit. exp. Path. u. Ther., 1914 (15), 116. 



3' Czyhlarz and Fuchs, Biochem. Zeit., 1914 (63), 131. 



38 Scott, Amer. .lour. Anat., 1916 (20), 237. 



39 M. R. Lewis, Science, 1918 (48), 398. 



