PATHOLOGICAL FAT ACCUMULATION 337 



is shown by part of the fat to extraction with ether. A certain 

 proportion of the fat can be extracted readily in twenty-four 

 hours or less by ether, but after this time no more can be made to 

 leave the tissues. Apparently the rest of the fat is held in a 

 combination (which seems to be chemical rather than physical) 

 that is insoluble in ether. By digesting the tissue for a short 

 time by pepsin, however, the rest of the fat becomes freed (sug- 

 gesting that it is the proteids with which it is combined), so that 

 it can then be readily dissolved out in ether. 1 We see, there- 

 fore, that much of the fat of normal cells is so firmly combined 

 that it cannot be dissolved in ether, and under normal conditions 

 all, or nearly all, of it cannot be stained. (This applies partic- 

 ularly to the parenchymatous organs ; the fat of the areolar 

 tissue is all readily extracted Taylor.) But when pathological 

 changes in the cells result in decomposition of the cell proteid 

 through autolysis, part of this normally invisible fat is set free, 

 and, becoming visible, produces the so-called " fatty degenera- 

 tion." This explains the observations of Rosenfeld, cited 

 above, that kidneys may show much fat to the naked eye and 

 microscopically, when they actually contain even less than nor- 

 mal amounts of fat. Taylor 2 advanced this explanation, and 

 supported it experimentally by showing that during fatty degen- 

 eration this protected fat actually is liberated, some two-thirds 

 becoming ether-soluble in an experiment performed with 

 phosphorus-poisoned frogs. As further support may be men- 

 tioned the fact that organs undergoing experimental autolysis 

 show microscopically an apparently typical fatty degeneration, 

 although analyses show that no actual increase in fat occurs. 3 



Relation of Anatomical to Chemical Changes. 

 From the facts brought out in these various experiments we 

 must consider that the anatomically established condition of 

 "fatty degeneration" represents either or both of two con- 

 ditions : (1) It may result from an increase in the normal 

 quantity of fat in an organ undergoing parenchymatous degen- 

 eration, through an infiltration of fat from the outside ; this is 

 particularly true of the fatty degeneration of the liver ; (2) or 

 there may be no increase in the total amount of fat, but the 



1 Chloroform will separate this fixed fat from the tissues ; and alcohol- 

 hardened tissues hold much less of the fixed fat than 1 do dried tissues. 



2 Jour. Med. Research, 1903 (9), 59. 



3 Kraus, Arch. exp. Path. u. Pharm., 1886 (22), 174; Siegert, Hofmeister's 

 Beitr., 1901 (1), 114. Waldvogel (Virchow's Arch., 1904 (177), 1), however, 

 claims that the " protagon " and " jecorin " increase in autolyzing organs, while 

 the lecithin decreases, and believes that proteids may indirectly give rise to 

 fat. There are numerous questionable features concerning these results, and 

 they cannot be considered as final. 



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