402 RETROGRESSIVE CHANGES 



short time by pepsin, however, the fixed lipins beeome freed, so that 

 they can then be readily dissolved out in ether. AVe see, therefore, 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 particularly to the paren- 

 chj'matous org'ans; the fat of the areolar tissue is all readily ex- 

 tracted — Taylor.) By the use of Ciaccio's method for microscopic 

 demonstration of intracellular lipoids. Bell ^^ has been able to dem- 

 onstrate in those cells that are fat-free by ordinary methods sufficient 

 lipoidal material to account for the normal "invisible fat," which is 

 probabl}' identical with the "liposomes." But when pathological 

 changes in the cells result in decomposition of the cell protein through 

 autolysis, or produce physical clianges in the colloids that hold the 

 lipins emulsionized, part of this normally invisible fat is set free, and, 

 becoming visible, "plianerosis," ^^ produces the so-called "fatty degen- 

 eration." 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 normal amounts of fat. 

 Taylor ^^ advanced this explanation, and supported it experimentally 

 by showing that during fatty degeneration this protected fat actually 

 is liberated, some two-thirds becoming ether-soluble in an experiment 

 performed with phosphorus-poisoned frogs. Mansfeld ^^ also found 

 that in animals poisoned with phosphorus, the proportion of fat which 

 is present in a form free from protein union in both blood and viscera, 

 is increased, while the firmly bound fat is decreased. As further 

 support may be mentioned the fact that organs undergoing experi- 

 mental autolysis show microscopically an apparently typical fatty de- 

 generation, although analyses show that no actual increase in fat oc- 

 curs.'^ 



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 conditions : ( 1 ) It may result from an increase 

 in the normal quantity of fat in an organ undergoing parenchymatous 

 degeneration, through an infiltration of fat from the outside; this 

 is particularly true of the fatty degeneratioji of the liver, pre- 

 sumably because the liver normally receives the relatively saturated 

 body fats to work them over into the more labile desaturated fats; (2) 



i3lntornat. Monats. Anat. u. Physiol., mil (28), 297; Jour. :\I(m1. I^cs.. 1011 

 (24), 5.39. 



14 Klompcrer, Dent. mod. Wocli.. 1909 (35), 89. 



in .Tour. Med. Research, 190.3 (9), 59. 



1'! Pfliipor's Arch., 1909 (129). ti;\ 



17 Dietrich, Arb. path. Inst. Tiilrngeu, 1900 (5). IT. 3; Hess and Saxl. Virchow's 

 Arch., 1910 (202), 149: Ohta. T?iochen). Zeit.. 1910 (29). 1; Siiihata, ihid.. 1911 

 (31), 321. Tile sif,'nificance of tlie increase of li|iins observed in ])erfused l<idncvs 

 by dross and Vorpaiil is made duulitful 1)V ilie urlirh^ of riKhMliill mid lleiulrix.. 

 Jour. Biol. Chem., 1915 (22), 471. 



