THE FUNCTIONS OF THE DIGESTIVE ORGANS. 519 



bile and its constituents, namely the bile-salts, accelerate the secretion of 

 bile. Experiments carried out in this direction leave it uncertain for the 

 present as to what significance we shall give to this resorption process. 



Since it was not known precisely what role the bile played in diges- 

 tion, it has been assumed to be quite different by different scientists. 

 Some have held that the bile had an antiseptic action. It had been 

 observed that animals with a biliary fistula showed increased putrefaction 

 in the intestines. Direct experiments upon the bile itself have shown that 

 it indeed tends to restrain the action of certain bacteria, but that it is by 

 no means a good antiseptic agent. Furthermore, if fat be entirely excluded 

 from the food, or only a limited amount of it given to animals with such 

 a fistula, the intestinal putrefaction is not greater than under normal 

 conditions. It was, therefore, not so much the absence of the bile that 

 caused the observed putrefaction, but rather the faulty absorption of the 

 fats. 



Bile has, further, been thought to have an influence upon the peristalsis 

 of the intestines. The extent of such action, under normal conditions, is 

 still undecided. It has also been observed that if bile is added to a peptic 

 digesting fluid a precipitate will be formed at once. Now normally the 

 acid chyme passes out of the stomach mixed with pepsin into the duode- 

 num. It might be thought that the action of the pepsin, which is no 

 longer desired in this part of the intestine, is stopped by the bile precipi- 

 tating pepsin with the albumin and its higher cleavage-products. It has, 

 however, never been possible to establish satisfactorily the formation of 

 such precipitates in the intestines, so that at present we are hardly justi- 

 fied in assuming that this test-tube experiment represents the normal 

 condition. At the same time it does seem probable that the bile prevents 

 the further action of the pepsin. 



We have already touched upon one quite essential function of the bile, 

 namely its role in the absorption of fats. We have seen that a large part 

 of the fats, or perhaps even all, is decomposed into its components the 

 fatty acids and glycerol. The bile is an excellent solvent for these fatty 

 acids and the soaps (the salts of these acids), and on account of this 

 fact a great importance has been ascribed to the bile in assisting the absorp- 

 tion of the fats and their cleavage-products. Before this action of the bile 

 had been verified by direct experiment, it had been observed that if, for 

 any reason, the flow of bile into the intestine was prevented, the faeces 

 showed a pronounced pale color, and when a considerable amount of fat 

 was present in the food it was at once obvious that undigested fat was 

 present. Other facts indicate a faulty absorption of the fats in such cases. 

 In animals with biliary fistula, where the bile was taken away, animals 

 decreased rapidly in weight, although fed with the same nourishment 

 that had previously agreed with them. It is clear that the loss of a 



