156 THE DIGESTIVE FLUIDS. 



which are normally found in the intestinal canal. We accordingly 

 find that in animals and in man the processes of nutrition are in no 

 way interfered with if the bile is prevented from entering the 

 digestive tube, but is carried to the outside through the establish- 

 ment of a fistulous opening in the common duct, provided that food 

 is administered which contains but little fat. With a diet consist- 

 ing of albumins and carbohydrates digestion thus continues unim- 

 paired, and the animal is capable of maintaining its nitrogenous 

 equilibrium practically as before. If fats, however, are given at the 

 same time in large amounts, more or less serious digestive disturb- 

 ances soon develop and the animal loses weight. In such cases it 

 has been ascertained that whereas normally from 2 to 10 per cent, 

 of the ingested fat is eliminated in the feces, from 31 to 47 per cent, 

 now escapes resorption. The offensive gases which are then passed 

 by the animal are referable to an increase of the putrefactive 

 processes in the intestines. This is, however, not owing to the 

 absence of bile per se, but to the fact that the unabsorbed fats 

 envelop the albuminous material, and thus prevent its further diges- 

 tion, so that in the lower portion of the digestive canal, where the 

 putrefactive processes are most intense, the bacteria find an increased 

 amount of pabulum at their disposal, and an increase of the putre- 

 factive products accordingly results. In the presence of bile, on the 

 other hand, this does not occur, as its emulsifying effect upon the 

 fats hastens their digestion, and thus leaves the albumins exposed 

 to the action of the digestive juices, and to their resorption in turn. 

 Indirectly, it can thus control putrefaction, but such action is not 

 due to any germicidal or antiseptic properties of its own. On with- 

 drawing fats from the food and giving an adequate supply of carbo- 

 hydrates, normal relations are soon re-established, though the bile is 

 absent as before. 



The bile in reality represents a most important excretory product 

 of the animal body, and may in this sense be compared to the urine. 



Secretion. As found in the gall-bladder, the bile represents the 

 secretory product of the liver-cells which is eliminated into the 

 radicles of the biliary passages, together with so-called mucus which 

 is derived from the epithelial lining of the greater trunks and the 

 gall-bladder itself. Its secretion is continuous, but liable to exacer- 

 bations which are essentially dependent upon the ingestion of food. 

 According to Heidenhain, the curve of secretion, in reference to 

 amount, shows two periods of greatest activity, which in the dog 

 correspond to the third to the fifth and the thirteenth to the fifteenth 

 hour, respectively, after the administration of food. This curve, 

 however, is further influenced by the character of the food ingested. 

 With an albuminous diet three stages of maximal secretion are 

 thus noted : The first after two to three hours, a second stage 

 after five to eight hours, and a third stage after twelve to fourteen 

 hours. With a diet of albumins and fats, on the other hand, the 

 period of greatest secretion occurs after eleven to twelve hours, 



