256 APPLIED PHYSIOLOGY 



extent,* probably as the result of bacterial action. The 

 presence of large quantities of fat in the stools should 

 therefore suggest pancreatic disease or blocking of the 

 duct. 



From its action in digestion bile is entitled to rank as 

 a secretion. Its properties as an excretion will be con- 

 sidered in another chapter (p. 282). 



The chief use of bile in digestion consists in the power 

 it possesses of increasing the breaking up and absorption 

 of fat, which resides, as Starling says, t ' in its power of 

 serving as a vehicle for the suspension and solution 

 of the interacting fats, fatty acids, and fat-splitting 

 ferment.' This is due to the peculiar physical properties 

 of the bile salts along with those of the lecithin and 

 cholesterin which they hold in solution. Hence it is not 

 surprising that when bile fails to enter the intestine the 

 loss of fat in the faeces is greatly increased,! and part 

 of the pale colour of the stools in jaundice is due to 

 this cause. In such cases fats should be withheld from 

 the diet. 



The antiseptic power of bile in the intestine has prob- 

 ably been exaggerated, but if free bile acids are present, 

 as they are when acid gastric juice is entering the 

 intestine freely, a certain degree of antiseptic power 

 is exerted. On the other hand, the increased amount of 

 intestinal putrefaction which undoubtedly occurs in 



* Vaughan Harley, Journ. of Pathology, 1896, iii. 245 ; se 

 also Krehl's c Clinical Pathology,' English translation, p. 280. 



f * Recent Advances in the Physiology of Digestion ' (Constable), 

 1906, p. 117. 



| Mueller, Zeit. f. Klin. Med., 1887, xii. 45. 



