FATTY DEGENERATION. 



23 



Fig. 5. 



Crystals of cholesterin, after 

 Virchow. 



parallel, but without overlapping each other at every point. 



The various and interesting forms 



assumed by this substance have been 



exhaustively studied by VircJiow ; we 



must, however, refer our readers 



to the accompanying w^oodcut and 



to the original paper (Vircliow'^s 



Archiv, xiL 101). Micro-chemical 



reactions are very useful in enabling 



us to distinguish cholesterin with 



certainty from other substances which 



have the same crystalline form. These 

 reactions are very characteristic. 

 A drop of concentrated sulphuric acid, when allowed to flow 



gradually over the specimen, effects a progressive liquefaction 

 of the cholesterin plates at their edges, and makes them assume 

 a greasy appearance. After a little while the plate becomes 

 flexible and quasi-membranous ; it is occasionally folded on itself; 

 sometimes it shrinks together ; gradually, however, we see the 

 mass melting at its periphery, while a dark reddish-brown 

 globule is formed {Vv'choiv, Wiirzhurge)' VerJiancUungen, 1850, 

 Bd. i. s. 314). 



The simultaneous action of sulphm'ic acid and iodine produces 

 a fine blue colour during the first stages of the decomposition of 

 the cholesterm. As regards the presence of cholesterin in the 

 atheromatous pulp more particularly, the hypothesis that it is 

 first taken up by the oily and saponaceous constituents of the 

 emulsion, and then deposited when these are decomposed, un- 

 doubtedly accords best with what we know of its properties; 

 but this is a point which requires further investigation for its 

 settlement. 



§ 30, We have hitherto traced the course of fatty metamor- 

 phosis mainly as it occurs in individual cells. We have yet to show 

 how the phenomena of the process are modified in accordance 

 with the primary modifications in the form of the corpuscular 

 protoplasm. These modifications ai'e, of course, purely morpho- 

 logical. Thus, for example, w^e cannot expect the aggregation 

 of fat-granules to be perfectly spherical when the original cells 

 are stellate, with long processes ; far removed, therefore, from 

 the primitive spheroidal type. We may take the degenerated 



