456 CALCIFICATION, CONCRETIONS, AND INCRUSTATIONS 



the same time the desquamated cells and clumped bacteria offer 

 suitable nuclei upon which the cholesterol begins to crystallize out. 

 Apparently after the calculi have reached a certain size they cause 

 sufficient mechanical injury to keep up the cell degeneration and chol- 

 esterol formation, even after the infection has subsided. A certain 

 amount of infection and inflammation is a favoring condition, however, 

 for Harley and Barratt^*' found that fragments of cholesterol calculi 

 introduced aseptically into the gall-bladders of dogs were slowly dis- 

 solved and disappeared, but this was prevented by infecting the gall- 

 bladder with B. coll. According to Naunyn's investigations, it is 

 not an alteration in the composition of the bile, as formed in the liver, 

 which causes the precipitation of cholesterol, but rather the presence 

 of the nidus, and the production of large quantities of cholesterol in 

 immediate proximity to this nidus, that determines the formation of a 

 concretion. In case the bile stagnates in the gall-bladder, the choles- 

 terol that is being constantlj^ formed by the normal disintegration of 

 surface epithelium accumulates, until, even without infection, there 

 forms a sediment of soft yellowish and brownish masses, consisting 

 chiely of cholesterol and bilirubin-calcium. From this material 

 calculi may eventually form, and by their irritation lead to further 

 formation of cholesterol and increased growth." But bacteriological 

 studies indicate that generally an infectious influence is present in 

 cholelithiasis, and bacilli may be found alive in gall-stones for remark- 

 ably long periods. 



Recent applications of colloidal chemistry add much to our under- 

 standing of gall-stone formation. Thus, Lichtwitz points out that 

 the colloids of normal bile, all of which are electro-negative, may be 

 precipitated by positive serum colloids coming from the blood when 

 the gall-bladder is inflamed; hence we get a precipitate of cholesterol, 

 bilirubin and proteins. When the colloids are thus thrown down the 

 solvent power of the bile for the alkali earths it contains is decreased, 

 and so calcium or magnesium are added to the mixture. Cholesterol 

 is in solution in the bile as an emulsion colloid, and when stagnation 

 of the bile leads to absorption or disintegration of the chelates and 

 fats which keep it in solution, the droplets become confluent, and 

 then crystallization takes place (Schade) with formation of spheroliths, 

 and eventually a crystalline cholesterol calculus. If even the slightest 

 pressure is brought to bear on the myelin-like masses before they 

 crystaHize, however, they will be pressed into scales, and the common 

 laminated structure results; hence crystalline calculi are single, while 

 multiple gall-stones are laminated, with perhaps partial crj^stallization 

 between the lamellse. Also when the gall-stones result from inflamma- 

 tion, and there is much serum colloid present, the stones are lamellated 



88 Jour, of Physiol., 1903 (29), 341; see also Ilansemann, Virch. Arch., 1913 

 (212), 139. 



" Concerning the structure of gall-stones see Ribbert, Virchow's' Arch., 1915 

 (220), 20. 



