100 CYCLOSES, CHOLESTEROL AND CHOLIC ACID 



Neuberg-Rauchwerger's Reaction. This reaction is of exceptional 

 interest because it is also given by the bile-acids and certain other 

 derivatives of the terpenes. A common origin of the bile-acids (cholic 

 acid) and cholesterol is thus indicated. With rhamnose or better still, 

 with d-methyl-furfurol and concentrated sulphuric acid, an alcoholic 

 solution of cholesterol gives a pink ring, or after mixing the two liquids 

 and cooling, a pink solution. 



Lifschutz's Reaction. Dissolve a few milligrammes of cholesterol 

 in two c.c. of glacial acetic acid, add a few drops of benzoyl superoxide, 

 and boil. On adding four drops of concentrated sulphuric acid to the 

 solution a green coloration is obtained, which rapidly changes to violet, 

 then to blue. Oxidation-products of cholesterol yield this reaction 

 without preliminary treatment with benzoyl superoxide, and in this 

 way oxidation-products of cholesterol have been detected in the blood 

 and tissues, and especially in cholesterol-concretions (gall-stones) in the 

 gall-bladder. 



In plant-tissues there are found a variety of substances, the Phyto- 

 sterols, which are more or less closely allied to cholesterol. The best, 

 known of these is Sitosterol, an isomer of cholesterol, which occurs in 

 wheat, rye, linseed-oil and the calabar bean. It differs from choles- 

 terol in crystalline form, melting-point (137 contrasted with 148.5 for 

 cholesterol) and optical rotatory power. Its solubilities in various 

 organic solvents, and the color reactions which it yields are similar 

 to those of cholesterol. It is absorbed together with cholesterol from 

 the intestine. 



In fungi a series of phytosterols are found which contain a smaller 

 proportion of hydrogen than cholesterol, and furthermore, differ from 

 cholesterol in not yielding Salkowski's reaction. 



BILE-CONCRETIONS; AMBERGRIS. 



The concretions which occasionally form in the gall-bladder are of 

 three types, formed respectively of Calcium Carbonate, Bile-pigments 

 and Cholesterol, Each of these types of gall-stones is usually con- 

 taminated with a larger or smaller proportion of the constituents of the 

 other types. The cholesterol-stones have a waxy glistening and cry- 

 stalline fracture, and are frequently deposited in concentric layers. 

 They are often facetted by the pressure of adjacent stones, while their 

 color is sometimes white, but more frequently tinged with bile-pigments. 



The cholesterol-stones are the type which most frequently occur in 

 man. The conditions leading to their formation are unknown but it is 

 parhaps a significant fact, in view of the accumulation of cholesterol in 

 the tissues with advancing age, that the incidence of cholelithiasis 

 increases progressively with the advance of years, over 75 per cent, of 

 cases occurring in persons over forty years of age. It is furthermore 

 stated that cholelithiasis is more frequent in carcinomatous than in 

 non-carcinomatous subjects. 



