

190 W. ft. BLOCK 



to acid, being destroyed by a fifteen minutes' exposure to 0.2 per cent 

 hydrochloric acid, and that if the acidity was reduced either by ordinary 

 neutralization with alkali or by protein a fairly good lipase action could 

 be demonstrated (about five times as great as that of the succus entericus). 

 Tlio practical bearing of their work was to indicate that after a meal and 

 before the stomach acidity had reached a value high enough to destroy 

 the lipase (being kept down by the proteins of the food) considerable 

 fat splitting might take place, at least of emulsified fats. 



The sum of the work to date leaves little doubt that a lipase is secreted 

 by the stomach. Whether there is much fat splitting will depend on a 

 number of factors among which are the following: (a) The acidity of the 

 stomach contents high acidity destroying and lower acidity down to a 

 certain point inhibiting the activity of the gastric lipase. The degree of 

 acidity is dependent on the amount of acid secreted and on the amount 

 of neutralizing substance (mainly protein) present. The presence of fat 

 inhibits acid secretion, (b) The state of division of the fat. Since the 

 lipase and the fat have no mutual solvent, the splitting can take place 

 only at the surface of the fat particles, and unless these are very small and 

 the surface correspondingly great (as in an emulsion) not much splitting 

 is likely. The acidity of the stomach is probably rarely weak enough 

 to permit the formation of soap emulsions so that the lipolytic activity of 

 the gastric juice would be confined to natural emulsions as milk, etc. The 

 splitting of the fat in these emulsions may be very considerable ("Volhard). 

 (c) The length of time the fat remains in the stomach. The presence 

 of much fat slows the passage of food from the stomach (Cannon), giving 

 more time for tho gastric lipase (and also the regurgitated pancreatic 

 lipase) to act. 



Absorption. Klemperer and Scheuerlen, by ligating the intestine of 

 dogs below the pylorus and weighing fat before and after 3 to 6 hours in 

 the stomach, found that none had been absorbed. The objection might 

 be raised in this case, as in many similar ones, that the operative pro- 

 cedures were responsible for the failure. Histological observations from 

 von Kolliker onwards have demonstrated fat droplets in the gastric epi- 

 thelium although none were seen in the lymphatics. Weiss believed that 

 absorption into the epithelia was confined to young animals, in which 

 belief he is opposed by Greene and Skaer, who found absorption (into 

 the epithelium) in both young and old animals and also that the amount 

 of absorbed material (observed by staining) and the depth of penetration 

 depended on the length of stay of the fat in the stomach. The histological 

 picture was found by these observers to resemble strongly the appearance 

 of the intestinal nuicosa during fat absorption. After the fat left the 

 stomach the cycle reversed and the fat disappeared (back into the 

 stomach?). 



Mendel and Baumann studied the absorption of fat by the stomach 



