631 BILE other choloie. According to tho researches of Bensch and Strecker, the choleate of soda is the chief principle of bile, as regards its relative quantity, and also its importance. The choleic acid is a nitrogenized substance, containing sulphur in greater proportion than the other nitrogenized matters. As in the bile of most animals sulphur exists only in the choleic acid, and in the proportion of 6 per cent., it is pos- sible to ascertain easily the quantity of this acid in any kind of bile. It has thus been found that almost the whole of the alcoholic extract of bile consists in choleic acid in the fox, the sheep, the dog, &c., while in the bile of the ox there is as much cholio as choleic acid. The salts formed by these two acids amount to at least 75 per cent, of the whole of the solid con- stituents of bile. Normal human bile contains, according to Frerichs, about 14 per cent, of solid constituents; butLehmann justly remarks that the quantity of water, and consequently the proportion of solid constituents, may be as variable in bile as in most of the other secre- tions. Gorup-Besanez found 9'13 per cent. of solid constituents in the bile of an old man, and 17'19 per cent, in that of a child aged 12 years; but many more proofs are necessary to determine that bile is more aque- ous in old age than in childhood. Lehtnann says that the organic constituents of human bile amount to about 87 per cent, of the whole solid residue. The proportion of the other elements of bile, i. ., bile pigment (bili- verdine), cholesterine, fats, and mineral salts, has not yet been positively determined. The two special organic acids of bile can be decom- posed into various substances. They both, when treated by alkalies, give origin to cholalic acid, and to dyslysine, but one of them (the cholic acid) produces also glycocoll, and the other (the choleic acid) taurine. When treated by powerful acids, cholic acid gives origin to choloiidic acid, glycocoll, and dyslysine, while choleic acid produces taurine, choloiidic acid, and dyslysine. Cholesterine and margaric and oleic acids are kept in solution in bile by the two principal organic acids of this secretion. The biliverdine, or the coloring principle of bile, is a substance resembling in its composi- tion the hematosine or coloring principle of blood. It contains nitrogen and iron, as do all the organic coloring matters, according to M. Verdeil. The biliary sugar, or picromel, seems to be only a product of decomposition of some of the constituents of bile. The biline of Ber- zelius and Mulder seems to be a mixture of al- kaline cholates and choleates. The ancient physicians and physiologists used to consider the organ which secretes bile, the liver, as a most important one ; but after Aselli, in 1622, had discovered the lymphatic vessels, a reac- tion took place against the importance attribu- ted to the liver, and some physiologists went so far as to think that its share in the vital actions was almost null. In France the researches of many physiologists, and particularly of Prof. Bernard, have shown that the liver is one of our most important organs, and recent experi- ments have proved that bile is a very useful secretion, if not an essential one. Schwann opened the abdomen and the gall bladder in many dogs, and succeeded in forming a biliary fistula, after having tied the bile duct. Nine of these animals very quickly died ; six lived 7, 13, 17, 25, 64, and 80 days; two only survived definitively, but in them a new bile canal was formed. Of the six dogs that lived from 7 to 80 days, four seemed to die starved, having lost their fat. The two others after a few days began to regain their fat, and reached their initial weight up to a certain time, when they became again emaciated and finally died. Blondlot has seen a dog living five years after the occlusion of the bile duct, and the forma- tion of a biliary fistula, through which the bile flowed out. During this long period the health of the animal was usually very good. More recently Schwann has repeated his experiments on 20 dogs, out of which only two survived, one four months, and another a year. Nasse kept a dog alive five months with a biliary fis- tula. Its appetite was good, and it ate about double the quantity of meat that a healthy dog of the same size would have taken, and never- theless it died almost completely deprived of fat. It results from very careful experiments of Bidder and Schmidt, and of their pupil Schell- bach, that the cause of death, when bile is not allowed to flow into the bowels and passes out of the body, is that the animal has a great difficulty in repairing the loss of fat and of ni- trogenized substances which go out with the bile. In a dog operated upon by these physi- ologists, the quantity of food taken was much greater than before the operation, and the con- sequence was that the animal did not lose his forces and remained fat, though less so than before. Prof. Bernard, according to Dr. Por- chat, has ascertained that if adult dogs may live many months when bile flows out of their body by a biliary fistula, it is not so with young dogs, in which death always occurs quickly in such circumstances. Some facts observed in men (in children by Dr. Porchat, in adults by Dr. Budd) seem to prove also that adults may live much longer than children when there is no bile passing into the bowels. It seems very probable that bile is not absolutely necessary to digestion, as some animals have lived a long while without bile ; but even in these cases there is room for doubt. For instance, Blond- lot's dog was not prevented licking its wound, and probably swallowed a little bile, as Schwann has seen his dogs doing ; and Bidder and Schellbach, we cannot understand why, at times gave pieces of liver (containing bile) as food to the one of their dogs that was the least affected by the operation. We may sum up thus: 1. Bile has not yet been positively proved not to be absolutely necessary to diges- tion and to life. 2. It seems probable, how- ever, that its function is not absolutely essen-
