ALIMENTARY TRACT AS AN ABSORPTIVE SYSTEM. 291 



objections. The cleavage products of fat are readily soluble 

 in the fluids and tissues of the body and diffuse with great 

 rapidity. 



The exact form in which the cleavage products are absorbed 

 cannot as yet be looked upon as settled definitely. For the 

 sake of simplicity we will adopt MUNK and LOEVENHART'S 

 opinion that fat is absorbed as fatty acid and alcohol. This 

 is probably correct, though it is at variance with the belief 

 of certain other investigators that the fatty acid unites with 

 the alkalies of the body and forms soaps. Whichever may 

 ultimately have to be adopted will not alter the fundamental 

 principles of the mechanism of fat absorption. Since certain 

 of the fatty acids are practically insoluble in water, and 

 since solubility is so important a factor in absorption, it is 

 well to bear in mind MOORE and ROCK WOOD'S experiments, 

 which show that the insoluble fatty acids become freely soluble 

 in the presence of bile. 



It is well to impress anew upon the reader that lipase, 

 which we ordinarily think of as a constituent of the pan- 

 creas and the pancreatic juice only, is really very widely 

 distributed throughout the body, where it occurs in different 

 amounts in practically every tissue and fluid. Of immediate 

 interest to us is the fact that lipase occurs in the mucosa of 

 the intestine as also in the lymphatic glands, lymph, and the 

 blood. 



Bearing in mind the facts stated above regarding lipase, 

 its action and its distribution, let us trace the chemical changes 

 which follow the ingestion of a fat. This substance is not 

 acted upon in the mouth or oesophagus. As lipase is found 

 in the gastric juice and gastric mucosa it is possible that 

 some digestion may occur in this viscus. This will occur 

 especially if the meal has been one which calls forth a secre- 

 tion of but little hydrochloric acid or if the digestion occurs 

 in a stomach which through pathological change is secreting 

 a deficient amount of this acid. The activity of the lipase 

 under these circumstances is not interfered with. It is 



