BILE, CHOLESTERIN, CHYLE. 1049 



which generally consist of this substance combined with a 

 portion of the yellow colouring matter of the bile. Cholesterin 

 may be obtained by digesting these concretions in a solution 

 of potash, by which the colouring matter is readily dissolved, 

 and the cholesterin left white ; or by dissolving them in boiling 

 alcohol, in which the colouring matter is insoluble. 



Cholesterin crystallizes from an alcoholic solution in colourless 

 small plates, of a pearly lustre ; is insoluble in water, tasteless, 

 fuses at 27S6 (137 centig.), and solidifies again in a crystalline 

 condition. If strongly heated apart from air, it sublimes 

 unchanged in a great measure, and condenses in plates. It is 

 but sparingly soluble in cold alcohol ; is not altered by caustic 

 alkalies. 



The bile appears to act as a stimulus to the intestinal canal 

 generally and to assist in dividing the chyme into chyle and 

 fecal matter, by combining with the latter. 



Chyle. This is the fluid absorbed by the lacteal vessels 

 from the small intestines during the process of digestion. As 

 drawn from the thoracic duct of a mammiferous animal, it is an 

 opaque milky liquid, in which two kinds of globules are per- 

 ceived by the microscope* This liquid has already a consider- 

 able resemblance to blood; it soon coagulates; the clot reddens 

 in the air and contains fibrin. The serum which separates is 

 composed, with the usual undetermined animal substances and 

 salts, principally of albumen and fat, which last comes to the 

 surface, and is what constitutes, without doubt, one of the two 

 species of chyle-globules. 



Excrements. The excrements of man usually contain about 

 25 per cent of solid matter, which necessarily varies consider- 

 ably with the nature of his food. Besides the indigestible 

 residue of the food, it contains mucus, an undetermined ex- 

 tractive matter, fat, salts and the whole constituents of the bile, 

 to which it owes its colour. From the incineration of 100 

 parts of dried excrements, 15 parts of ashes have been obtained, 

 which were principally composed of the phosphates of lime 

 and magnesia. The value of night soil as manure is ascribed 

 chiefly to these salts, and salts of ammonia from the urine. 



