This physiologist applied a ligature around the choledoch duct of an animal so as completely to prevent the bile from entering the duodenum, and then noted the effects produced on the digestion of the food immediately before and immediately after the operation. The experiment was repeated several times, and the result was uniform.
The production of the chyme in the stomach took place as usual, but the conversion of the chyme into chyle was immediately and com pletely interrupted. Not the smallest trace of chyle was perceptible either in the duodenum or in the vessels which take up the chyle when formed, namely, the lacteals.
It was at one time supposed that after the bile had performed this function that its compounds were thrown off from the system by the bowels. But that the bile is not merely an excrementitious fluid, intended to remove effete matter from the blood, but a secretion essential to the animal economy, was rendered almost certain by the experiments of Berzelius, Theyer, and Schlosser, which showed that the human faeces contained much too small a quantity of a substance resembling bile, to justify the idea that it was evacuated in this manner.
A further proof that the bile is absorbed and not excreted is afforded by an examination, made by Enderlin, of the ash yielded by the contents of the different portions of the intestinal canal of a hare.
He found that the ash from the contents of the duodenum alone effervesced on the addition of an acid, thus showing that the choleate of soda (which yields the carbonate on incineration) is absorbed before reaching the jejunum. Schwann also established this opinion
beyond a doubt, by a series of well-devised experiments ou dogs. He tied the ductus choledochus, and at the same time formed a fistulous opening in the gall-bladder, by which the bile escaped externally.
His most important conclusions are—lst, that when the bile does not get into the bowel its absence is generally perceptible in dogs about the third day by a marked diminution in weight; and, 2nd, that unless the channel for the conveyance of bile to the duodenum is re established, symptoms of deficient nutrition, wasting, debility, &c., ensue, and death is the ultimate consequence.
Upon this ground it was suggested by Liebig that probably all the carbonaceous substances of the food were converted into bile before being again taken up into the circulation and converted into carbonic acid for the supply of animal heat. It is however certain that a portion of the bile, in the form of colouring matter, passes off through the intestines, and also that in certain diseases it is thrown off in considerable quantities with the contents of the bowels. It can also bo shown that the quantity of biliary matter formed in the liver does not contain more than one-sixth or one-eighth of the quantity of carbon that is thrown off from the lungs in the form of carbonic acid. (Simon, Animal Chemistry ; Lehmann, Physiological Chemistry ; Caipenter, Manual of Physiology ; Gregory, hand-Book of Organic Chemistry ; (lyclopordia of Anatomy and Physiology, article Bile' ; Liebig, Animal Chemistry.)