JUIJAUY CALCULI 449 



traces of copper/"' iron, and iiiang-anese." The quantity of bile salts, 

 the chief constituent of the bile, is usually extremely minute, appar- 

 ently only so much as may percolate into the crevices of the concre- 

 tion. However many stones there may be in a gall-bladder, they 

 usually are all of approximately the same composition and structure. 



In o-all-stones from the domestic animals the i)rop()rtion of inorganic 

 salts is usually much higher than it is in man. 



Naunyn has classified gall-stones according to their composition, as 

 follows : 



1. "Pure" Cholesterol Stones. — The purity is only relative, since 

 even the ])urost always contain some pigment as well as a stroma 

 and a nucleus; but the amount of cholesterol may reach 98 per cent., 

 and is usually over 90 per cent. Crystalline structure is usually 

 well marked, while stratification is slight. The color varies from 

 nearly ]iure white to yellow, or even brown on the surface. 



2. Laminated Cholesterol Stones. — These consist of about 75-90 

 per cent, of cholesterol, and differ from the preceding form in con- 

 taining more pigment, which is deposited in layers alternating with 

 the white layers of cholesterol. The pigrment here, as in all other 

 gall-stones, consists always of the calcium salts of the pigments — 

 not of pure bilirubin and biliverdin themselves. Considerable calcium 

 carbonate is also usually present, particularly in the green layers of 

 biliverdin-calcium. 



3. Common Gall-bladder Stones. — The composition of this form is 

 but little different from the above, the chief difference being in the 

 structure. They present externally a firmer crust, usually distinctly 

 laminated ; in the center is a softer pigmented nucleus which fre- 

 quently shows a central cavity containing fluid. Such calculi are not 

 distinctly crystalline in structure, and are small, seldom larger than 

 a cherry. 



4. Mixed Bilirubin-calcium Calculi. — These generally occur singly, 

 but sometimes in groups of three or four, and are of large size. 

 Although the chief constituent is bilirubin-calcium, there is always 

 much cholesterol, often over 25 per cent. Copper and traces of iron 

 may also be present. Their structure is laminated, with sometimes 

 a crystalline cholesterol nucleus. 



5. "Pure" Bilirubin-calcium Calculi. — In addition to the chief con- 

 stituent, 'biliverdiii-calcmm, hilifuscin and hilihumin ^^ are practically 



56 See Mizokuclii, Cent. f. Pathol., 1912 (23), 3.37. 



57 Gall-stones have been found enclosing droplets of merpury. (Xaunyn. 

 Frerichs. ) 



39 Biliverdin differs from hiliruhin in containing- one more atom of oxygen in 

 the molecule, and it is easilv formed from Ijilirubin — even exposure to air will 

 slowly bring about the oxidation. Bilifuscin is a still more oxidized deriva- 

 tive — so much so that it does not give Gmelin's reaction (with PTXO. + HNOj) 

 for bile-pigments. Bilihumin represents the most oxidized of these products, 

 is brown in color, and is the chief constituent of the residue left after treating 

 gall-stones with ether, alcohol, and chloroform to dissolve out the cholesterol. 



29 



