388 NAUNYN'S VIEWS. [BOOK n. 



glassy structure, but sooner or later the cholesterin commences to 

 crystallise 1 . 



Whenever this remarkable development of small calculi from 

 clumps of cholesterin could be observed, Naunyn always found other 

 very minute cholesterin calculi, which, however, contained a central 

 cavity filled with a brown, softish, mass, composed mainly of bilirubin- 

 calcium, and he was able, in the case of these also, to study the 

 process of formation from its very commencement. At first, aggre- 

 gations of swollen epithelial cells are usually seen, which break down 

 to form a granular, brownish, mass and, in the immediate proximity, 

 similar brown granular masses are seen, around which confluent 

 myelin forms have set, forming a glassy capsule of cholesterin. 



It is impossible to reproduce Naunyn's interesting description of 

 the minor variations which may be observed in the mode of origin of 

 calculi and, for a knowledge of these, the reader is referred to his 

 work. It only remains for us to point out how, according to Naunyn's 

 investigations, the calculus grows and is modified. The growth of 

 calculi composed mainly of bilirubin-calcium occurs, doubtless, in 

 consequence of actual precipitation of the compound from the bile, 

 occasioned partly by the pouring out of a secretion rich in lime salts 

 from the walls of the gall-bladder (an event which, as we have seen, 

 always accompanies a catarrhal condition of the gall-bladder), but 

 partly, perhaps, in consequence of the simultaneous passage into the 

 bile of albumin, the presence of which greatly aids the precipitation. 



The growth of a calculus through the addition of cholesterin 

 generally occurs, according to Naunyn, by the superposition of, or 

 infiltration by, the masses of cholesterin around it, though where a 

 calculus is surrounded by bile it may also increase in size through 

 the crystallisation of cholesterin which was in solution in that liquid. 

 The infiltration, previously referred to, takes place through minute 

 canals which penetrate from the outer zone into the interior of 

 calculi so called infiltration canals (' Infiltrationscanale ') which 

 permit both the primitive soft cholesterin masses and the bile to 

 permeate the concretion. 



It must be added that, according to Naunyn, the crystalline 

 structure of cholesterin-calculi is not, in general, due to a primary 

 deposition of cholesterin in the crystalline form, but is due to a 

 secondary process of crystallisation which invades the mass of choles- 

 terin forming the calculus, after this has been deposited. 



1 The reader is referred to the most beautiful chromolithographs and photo-type 

 engravings illustrating the structure of gall-stones in Naunyn's book. 



