BILE

the fluid contained in the larger hepatic ducts, and in the gall-bladder, a special receptacle for it Though tolerably alike in all animals, it varies both as to the substances it contains and their amount. Tha bile of the pig end ox have been chiefly examined, not bo mnch that of man, account of the difficulty of obtaining it. As from the gall-bladder it has a colour varying yellow or yellowish green to greenish brown, sometimes to almost black; when fresh it has a unpleasant odour of musk, and a veiy bitter taste. Sometimes it is clear and limpid, at others muddy, from the separation of mucus, or thick black Hke tar. When the mucus romains in it, very soon putrefies, but if precipitated and removed, the bile can be preserved for a considerable time. Presh bile is neutral or slightly alkaline; after composition it is alkaline, and then inorganic begin to precipitate in it. In the bile of aniTnals large number of substances have been isolated identified. The most important are: the organic called biliary acids in combination with sodium pota ium; colouring matters, of which several been described; cholesterin, cholin, lecithin, taurine, fats, fatty acids combined with alkalis; inorganic salts, consisting of alkaline and alkaline earth chlorides, carbonates and phosphates, with traces of manganese, . These substances are all held solution by water, the proportion of which varies the bile oi different animals from 80 to 95 per Besides these, which exist normally in bile, there many other substances which are present in different diseases, and which may be fonned by the decomposition of some of the above named; various mineral substances also, such as arsenic, antimony, copper, pa into the bile, when they have been swallowed. The concretions called gall-stones vaxy a good in composition. The varieties are cla ified according to ikevt structure, colour, and ingredients. Some are crystalline, but they more oommonly have smooth soap -like appearance. They consist cholesterin, and are generally of a light colour. When the gall-stone is very dark it contains biliary colouring matter. The nurest kinds of gall-stones are those which are competed of inorganic salts, as calcic phosphate, and carbonate. The gall-stones uf animals are not unlike those of man just enumerated. The most curious are those from the antelope, called bczoarg (which see). Notwithstanding numerous investigations, function of the bile is by no means clearly understood, and on some points physiological chemists very nearly diametrically opposite opinions. Thus, for example, it is not certain whether it has a to play in digestion, or whether it is merely an cretion. Some hold that it acts as a solvent on tain parts of the food, others a ert that it has or no solvent action. However this may be, it seems probable that, if not directly, indirectly it a ists the absorption of food, and that as a very large portion of it returns into the circulation, it is not the other waste products of the body. It exeroises f luther an influence on fat, with winch it forms emulsion, and thereby facilitates its absorption diffusion. Purified bile has been employed washing fine woollen articles of dre , to avoid stroying their colour. 199