GROWTH, METAMORPHOSIS AND DEVELOPMENT 273 



must partly be regarded as solvents for the gallstone material. 

 Cholesterin precipitates in individual crystals from a supersaturated 

 aqueous solution of cholates; however a few drops of an oil suf- 

 fice to cause precipitation in an amorphous clump very similar to 

 the "myelin clump" which NAUNYN described as the (uranlage) 

 "precursor of gallstones" (Plate II, Fig. 52). After a few days, 

 radiating crystallization starts from the center (Plate II, Fig. 53), 

 oil droplets are released and may again give rise to oil-cholesterin 

 precipitates. In this way may be prepared, artificially, hard or more 

 or less plastic cholesterin stones, such as rarely occur, however, in the 

 gall bladder. The presence of fats or fatty acids is, therefore, a 

 requisite for their formation. For the precipitation of cholesterin 

 it is only necessary that the substances which hold it in solution, 

 the cholates and salts of the fatty acids, be destroyed. A priori, 

 a supersaturation with cholesterin is brought about in all processes 

 that interfere with the normal alkaline reaction of the bile, especially 

 infection with B. coli, B. typhosus, B. pyocyaneus and B. proteus. 

 I am inclined to accept the view of L. LiCHTwrrz* 1 that the acid for- 

 mation of these bacteria is chiefly responsible for the breaking down 

 of cholates and soaps, since staphylococcus aureus, which does not form 

 acid, causes no separation of cholesterin. The precipitation of 

 cholesterin can also be caused by sterile autolysis as well as by 

 rendering less favorable the conditions requisite to solution, since 

 cholates are absorbed by the walls of the gall bladder if the bile 

 stagnates there (congestion). 



Bilirubin forms amorphous precipitates with lime salts which 

 normally do not sediment out in the bile. In the presence of al- 

 bumin and fibrin, under conditions as yet not accurately studied, 

 calcium bilirubin may precipitate and include the albuminous in- 

 gredients, giving rise to clumps which in their cheesy structures 

 are very like natural calcium bilirubin stones (Plate II, Fig. 54). 

 In my opinion the neutral or faintly alkaline reaction of the bile 

 is essential for the development of a calcium bilirubin stone as op- 

 posed to the cholesterin stones, which require acidity. H. SCHADE* 

 considers that catarrhs, inflammatory and strongly exudative proc- 

 esses in which much lime enters the bile are responsible for the 

 formation of calcium bilirubin stones; this view explains the occur- 

 rence in them of albuminous ingredients. 



In some of the so-called mixed forms there may be an alternation 

 of processes which condition the separation of cholesterin and of 

 calcium bilirubin. 



An answer to the question whether a simultaneous precipitation of 

 cholesterin and calcium bilirubin may occur would be very interesting. 



