DIGESTION. 



181 



place, that bile is present in the intestine at all times, both during 

 digestion and in the intervals. This is shown by examination of the 

 intestine in dogs killed at various periods after feeding. "We have 

 always found, under these circumstances, evidence of the biliary salts 

 in the ether precipitate of the alcoholic extract of the intestinal contents, 

 in animals killed from one to twelve days after the last meal. The 

 biliary substances were recognized both by their solubility in water and 

 in alcohol, their insolubility in ether, their crystalline form, and by their 

 reaction with Pettenkofer's test. The secretion therefore continues to 

 find its way into the alimentary canal long after the animal has been 

 deprived of food. 



But the quantity of bile passing into the intestine in a given time is 

 much influenced by the digestive process, and its quantity is greatest 

 soon after the commencement of digestion. We have examined this 

 point by means of a duodenal fistula, made on the same plan as that for 

 gastric fistulae (Fig. 29). 



To ascertain the quantity of bile discharged into the intestine, and 

 its variations during digestion, the duodenal fluids were drawn off, for 

 fifteen minutes at a time, at various periods after feeding, and examined 

 as follows : each separate quantity was evaporated to dryness, its dry 

 residue extracted with alcohol, the alcoholic solution precipitated with 

 ether, and the ether-precipitate, representing the biliary salts present, 

 dried, weighed, and treated with Pettenkofer's test. The result is given 

 in the following table. At the eighteenth hour the quantity of fluid was 

 so small that the amount of its biliary ingredients was not ascertained. It 

 reacted, however, with Pettenkofer's test, showing that bile was present. 



DlSCHAEGE OF INTESTINAL AND BlLIARY FLUIDS FROM DUODENAL FlSTO.A IX A 

 DOG WEIGHING 16.5 KILOGRAMMES. 



The bile therefore passes into the duodenum in much the largest 

 quantity immediately after feeding. During the intervals of digestion 

 it accumulates in the gall-bladder ; and in animals which have been 



