406 RETROGRESSIVE CHANGES 



cent., also contains an increased amount when showing fatt}' degenera- 

 tion. The liver, however, takes on by far the greatest amount of fat 

 after "steatogenetic" poisons, ^^ and the microscopic picture usually 

 gives a very good approximation of the amount of lipins it contains. ^- 

 Apparently in these organs any excessive fat above the normal is 

 observable microscopically, although the normal lipin content is not, 

 and only in these three organs could Rosenfeld find an actual increase 

 in fat after poisoning with phosphorus, etc. It would seem, on the 

 other hand, that there is not often a real increase in the fat content of 

 the "fatty" kidney.^^ Normal spleen contains 14.2 per cent, of lipins, 

 and lung 17.3 per cent., but in both, "fatty degeneration" results in a 

 lowering of this quantity. Degenerations in the nervous tissue, which 

 Virchow considered the best evidence of the conversion of protoplasm 

 into fat, also show a marked decrease in lipins, and voluntary muscle 

 shows no increase in the normal quantity after poisoning. In general, 

 these experiments support the contention of Taylor concerning the 

 disclosure of the invisible fat through autolysis. -■* An explanation of 

 many of the discrepancies lies in the newer studies on 



The Relation of the Lipoids to Fatty Metamorphosis.-^ — Until 

 within a few years the significance of the intracellular lipoids in fatty 

 degeneration and related processes was not appreciated, beyond the 



^1 In fatty livers in phosphorus-poisoning the amount of fat may reach 75 per 

 cent, of the dry weight. Accompanying the fat increase are increase in water 

 and a relative or absolute decrease in proteins, probably due to cell autolysis. 

 In acute yellow atrophy a similar decrease in protein occurs, but without an in- 

 crease in fat. (See v. Starck, Deut. Arch. klin. Med., 1884 (35), 481.) 



22 See Helly (Beitr. path. Anat., 1914 (60), 1) who examined 100 human 

 livers which showed all variations in microscopic fat content, and chemically 

 from 7.36 to 74.43 per cent, of lipins (dry weight). He found that there was 

 usually a good correspondence between microscopic appearance and analytic re- 

 sults, altho some marked and unexplained discrepancies were observed. Gener- 

 ally the fat content was from 10 to 30 per cent, of the dry weight, with 19 to 

 21 per cent, the most common figures. When there is much fat present in the 

 liver the fat content of the bile is increased (Le Count and Long, Jour. Exp. Med., 

 1914 (19), 234). 



^^ This is contradicted by Landsteiner and Mucha (Cent. f. Path., 1904 (15), 

 752), and by Lohlein (Virchow's Arch., 1905 (180), 1) and Rosenthal (Deut. 

 Arch. klin. Med., 1903 (78), 94), but is supported by Orgler {ibid., 1904 (176), 

 413), and Dietrich, Verb. Deut. Path. Gesell., 1907 (11), 10. See also the later 

 studies by Rosenfeld on the effects of various steatogenetic poisons on different 

 organs, in Arch. f. Exp. Path. u. Pharm., 1906 (55), 179 and 344. It is probable 

 that the truth lies between the opposing views, namely, the kidney may under 

 some conditions take up fat from tlie blood, but it does so to a much less extent 

 than the liver, and it may sometimes show marked fatty change anatomically 

 without corresponding increase chemically. 



2'' Pieces of tissue implanted into animals may show a perii)lieral fatty meta- 

 morphosis or infiltration, yet show upon analysis a decreased fat content (Dietrich, 

 Verb. Deut. Path. Gesellsch., 1905 (9), 212).' 



^f* Literature by Leathes, "The Fats," London, 1910; Bang, Ergebnisse der 

 Physiol., 1909 (8), 463, also, "Chemie u. Biochem. d. Lijjoide," Bergniann, Wies- 

 baden, 1911; Kawanuu'a, Virchow's Arch., 1912 (207), 4()9, also "Die Cholester- 

 inesterverfcttung," Fischer, Jena, 1911; Asclioff, Zieglor's Beitr., 1909(47),!, 

 also Festschr. f. IJnna, 1911 p. 23; SchuUz, l<;rgel)nisse d. Pathol., 1909 (XIII;), 

 253; Ilanes, Bull. Johns Hopkins Hosp., 1912 (23), 77; Anitschkow and Chala- 

 tow. Cent. f. Pathol., 1913 (24), 1. 



