404 RETROGRESSIVE CHANGES 



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

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

 Yirchow 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 ]ii)oids in fatty degen- 

 eration and related processes was not appreciated, beyond the fact 

 that in most organs showing fatty changes the quantity of cholesterol 

 and lecithin is not greatly changed. In 1902 Kaiserling and Orgler 

 described under the non-committal name of "myelin" certain intra- 

 cellular droplets that may be found in the cells of the normal adrenal 

 cortex, and in amyloid kidnej^s, pneumonic exudates, tumor cells, 

 retrogressive thymus tissue, corpus luteum, and bronchial secretions, 

 and which differ from fat in being doubly refractile (anisotropic) 

 when viewed through Nicoll prisms, and in staining but slightly gray 

 with osmic acid, although taking up other fat stains well. 



As explained in Chapter i, the myelins are probably mixtures of 

 lipins, cholesterol-esters being prominent, and in many conditions in 

 which fat-like vacuoles are prominent in cells, leading to the diagnosis 

 of fatty degeneration, these substances are responsible, presumably 

 having been liberated from combination with the cell proteins in some 

 cases, in others actually being increased in the cell. This condition, 

 which Aschoff refers to as a cholesterol-ester fatty metamorphosis, is 

 especially seen in the parenchyma cells derived from the urogenital 

 anlage — that is, the adrenal cortex, kidney, testicle and corpus lu- 

 teum. Aschoff states that doubly refractile droplets can be formed 

 by lecithin and phosphatids generally, oleates, cholesterol esters, cho- 

 lesterol when dissolved in phosphatids or fats or fatty acids, as well 

 as by cholesterol esters dissolved in fats. Of these the most im- 

 portant quantitatively is the cholesterol ester group,-* and the anal- 

 yses of Windaus have sliown that in ])ath()l()gical processes the increase 



some conditions take up fat from the blood, but it does so to a much loss oxtont 

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

 without correspondin<j increase chemically. 



-- I'ieces of tissue im])lant('d into animals may show a peripheral fatty meta- 

 morphosis or intiltrat ion, xct show >i])on analysis a decreased fat content 

 (Dietrieh, Verh. Deut. Path." CJesellsch., IDOf) (n),'212). 



-s Literature by I.ieathea, "The Fata," London, 1!M0; l^anp, l\r<febnisse der 

 Physiol., 1009 (8), 4()3, also, "Chemio u. Biochem. d. Lipoide," Berfrmann. Wies- 

 l)aden, 1011; Kawamura, Virchow'a Arch., 1012 (207), 400, also "Die C'holester- 

 inesteryerfettunfr," Fischer, Jena, 1011; AschofT, Zie<rler's Beitr., 1000 (47), 1, 

 also Festschr. f. Unna, 1011, p. 23; Schultz, Erpebnisse d. Pathol., 1000 (XTITJ, 

 253; llanes, Bull. Johns Hopkins llosp., 1012 (23), 77: Anits.-hkow and Chala- 

 tow. Cent. f. Pathol., 1013 (24), 1. 



n^See also Verse, Ziegler's Beitr., 1011 (,'52), 1. 



