BILE is a fluid secreted from the blood by the liver. One part of it is destined to serve in the process of digestion; the other to be eliminated front the system. It is col ored yellow in man; that of graminivorous animals seems colored by the leaves they feed upon. The primary cells of the liver (the hepatic cells) separate the 13. from the blood of the portal vein, and discharge it into small ducts, which smite to form larger ones, and eventually the right and left hepatic ducts. The latter unite to form the com mon•hepatic duct, which is soon joined by that of the gall-bladder (the cystic duct). This junction forms the common B. duct, which pierces the second part of the duo denum, and running Obliquely in its wall for a short distance, opens on its mucous surface.
The secretion of 11. is constantly going on, and if there is food in the intestine, the bile mingles with it, and dissolves the fatty portions, preparatory to their absorption, the excrementitious portion of the 13. passing out of the body with the other indigestible materials. When the bowel is empty, the B. ascends the cystic duct, and is stored for future use in_a small-flask-like (the gall-bladder).situated tinder the liver.
Should, from any cause, the elements of the B. be in excess in the blood, or should the liver suspend the function of secreting it, not only is digestion imperfectly per formed, but the general health suffers from the impure condition of the Llood, and the patient is said to be /a/ow. On the other hand, the B. may be• secreted, bat its escape Interfered with, and then its reabsorption wiil produce jaundice (q.v.) Its said por
tions, again, especially the cholesterine, may be in excess, solidify, and produce binary calculi or gall-stones. See CALCULUS.
In chemical composition, 13. is essentially a soap analogous to resin-soap, and as ob tained from the ox, contains in 100 parts, Water 00.44 Biliary and fatty bodies, including resinoid acids............ 8.00 Mucus 0.
Watery extract, chlorides, phosphates; and lactates. 0.o5 Soda. 0.41 The soap is formed from the union of the re3inoid acids (glycocholic and laurneholie acids) with the soda. Human B. has the specific gravity of about 1020 (water = 1040), is of a ropy consistence, with a yellowish-green color; ,does not readily mix with water, but sinks therein, and only after repeated agitation becomes diffused through the water, which then assumes a frothy appearance resembling soap-suds. B. has a bitter taste, and a very sickening musky odor. It is interesting to observe that the 13. of salt water fishes contains potash Iu place of soda; although from their being surrounded by much common salt (chloride of sodium) in the sea-water, we should naturally expect to find soda in abundance; and the B. of land and fresh-water animals contains while, considering diet and habitat, potash might more naturally be looked for in largest quantity. B. performs several important functions in the animal economy, which will be found treated of under the article DIGESTION; see also the articles LIVER, and JAUN DICE.