450 CALCIFICATIOW ('<)\Cin:TI()\S, AM) IWhTSTATlOXS 



always present. liilihumiii is at times tlie chief iiiKi'eilient. and niay 

 form over half of the substance; bilicijanin is rarely present. There 

 is always some cholesterol, but sometimes onlj^ traces. These calculi 

 are small, from the size of a grain of sand to that of a pea, and they 

 occur in two distinct forms. One form is of wax-like consistence; the 

 other is harder. steel-<>Tay or black in color, with a metallic luster. 

 Pure bi]irul)iii and hiliverdin, not coinhiiicd with calcium, are prac- 

 tically never ]i resent in concretions. 



6. Rarer Forms. — (a) AniorpJwus (okI incomplete]]) cri/stdlJine cho- 

 lesterol gravel. Cholesterol externally giving' them a pearly luster: 

 pigment in the center. 



(6) Calcareous Stones. — Consist chiefly of a mixture of calcium 

 carbonate and bilirubin-calcium. Calcium carbonate may occur 

 either as a superficial crust, or as small masses within an ordinary 

 calculus; calcium sulphate and phosphate occur rarely in traces. 

 Stones consisting mainly of calcium carbonate are extremely rare in 

 man, but more frecjuent in cattle and other herbivora, in which all 

 forms of concretions contain much calcium, either combined with 

 pigment or as carbonate and phosphate. A calcium oxalate gall-stone 

 has also been described.*^" 



(c) Concretions ivith included bodies, and conglomerate stones. 



(d) Casts of Bile-ducts. — Occur particularly in cattle, and consist 

 chiefly of bilirubin-calcium. Rarely and imperfectly formed in man. 



Formation of GalUstones. — We owe much of our present under- 

 standing of the chemistry and pathology of the formation of gall- 

 stones to Naunyn "^ and his pupils. Former observers, having 

 learned that bile normally contains cholesterol (Hammarsten found 

 from 0.06-0.16 per cent, in human bile), sought the cause of gall- 

 stones in either an increased elimination of cholesterol by the liver, or 

 a decrease in the power of the bile to hold the cholesterol in solution. 

 Thus Frerichs, finding that the presence of large amounts of bile 

 salts and an alkaline reaction favored the solution of cholestei-ol, im- 

 agined that a diminution of either bile salts or alkalinity led to the 

 precipitation of the cholesterol. Naunyn and his pupil's, however, 

 observing that the amount of cholesterol present in the bile does 

 not depend upon the amount taken in the food or tlie amount present 

 in the blood, and that it did not vary in disease, exce]it when gall- 

 stones were present, concluded lliat the cholesterol of the bile is 

 neither a product of geiu'ral metabolism nor a specific secretion-prod- 

 uct of the liver. Finding that ])us and the secretions from inflamed 

 iiiiii'ous iiK'inbranes (bronchitis) contained as much cholesterol as did 

 iioniial bile, and often more, they concluded that the chief source of 



'^'1 Mniit lain-. Hull. sci. |pliaiiiiaf(il.. \'ol. IS, p. 111. 



'•' All l-^iifrlisli translation of tliis classic work, by .\. K. (iarrod, lias Iuhmi |)u1)- 

 lislicd by the Sydenham Society, ISiXi, vol. l.'iS. "Nfoio recently excejition has 

 been biken to certain of Nanii.\ii's \ icws, cs|)ccia]ly by AsdiolV and nacnicister. 

 "Cholelithiasis," Custav Fisclicr, .Iciia. l!l()!l. 



