164 PHYSIOLOGICAL CHEMISTRY. 



ular constituents of pigment-stones. Manganese and zinc have 

 also been found a few times. The pigment-stones are generally 

 heavier than water. 



The cholesterin-stones, whose size, form, color, and structure 

 may vary greatly, are often lighter than water. The fractured sur- 

 face is radiated, crystalline, and frequently shows crystalline, con- 

 centric layers. The cleavage fracture is waxy in appearance, and 

 the fractured surface when rubbed by the nail also becomes like 

 wax. By rubbing against each other in the gall-bladder they often 

 become faceted or take other remarkable shapes. Their surface is 

 sometimes nearly white and waxlike, but generally their color is 

 variable. The quantity of cholestrin in the stones varies from 642 

 to 981 p. m. (RITTEE). The cholesterin-stones also sometimes con- 

 tain variable amounts of lime-pigments which give them a very 

 changeable appearance. 



Cholesterin, C^H^O, or, according to REINITZER, C 27 H 47 0. 

 Cholesterin is generally considered as a monatomic alcohol of the 

 formula C^H^.OH. It yields a colored hydrocarbon (cholesteriline 

 or cliolesterone), of the formula C^H^, with sulphuric acid, and 

 this hydrocarbon is claimed by WEYL to be nearly related to the 

 terpene group It has also been claimed that it is closely allied 

 to cholalic acid. 



Cholesterin occurs in small amounts in nearly all animal fluids 

 and juices. It occurs only rarely in the urine, and then in very 

 small quantities. It is also found in the different tissues and organs 

 especially abundant in the brain and the nervous system, further 

 in the yolk of the egg, in semen, and in wool-fat. It appears (to- 

 gether with isocholesterin) in the contents of the intestines, in 

 excrements, and in the meconium. It occurs pathologically espe- 

 cially in gall-stones, as well as in atheromatous cysts, in pus, in tu- 

 berculous masses, old transudations, cystin fluids, excrements, and 

 tumors. Several kinds of cholesterih seem to occur in the plant 

 world 



Cholesterin which crystallizes from warm alcohol on cooling, 

 and that which is present in old transudations, contains 1 mol. of 

 water of crystallization, melts at 137 C., and forms colorless, trans- 

 parent plates whose sides and angles frequently appear broken and 

 whose acute angle is often 76 30' or 87 30'. In large quantities 



