526 LECTURE XXII. 



hardly right to believe that certain cells produce the ferments while others 

 merely give up salts. 



At all events, in considering the work of digestion, we are constantly 

 meeting with an extremely sensitive means for regulating the work of the 

 cells. They do not always act in the same way, but adjust their action 

 to the prevailing conditions. In considering the functions of the gland-cells 

 we gain considerable insight into the activity of the cells of the animal 

 organism in general. We are led to infer that even the individual cells of 

 the body are to a considerable degree dependent upon one another. They 

 adjust their work in the same way as the gland-cells, to the given condi- 

 tions. To be sure, it is perfectly possible, and in fact most probable, that 

 those cells of the body which are not directly connected with the work of 

 the intestine, are much more regular in their activity than the cells of the 

 intestine and the associated glands which are constantly meeting with new 

 conditions. The intestine forms a solid barrier between the heterogeneous 

 compounds in the food and the homogeneous building-material for the 

 blood and tissues, the composition of which has been established by the 

 entire development of the given animal species. The destructive activity 

 of the digestive ferments, together with the syntheses taking place in the 

 intestine, enables the cells of the body to work within certain limits always 

 under the same conditions. At the same time, the greater demands which 

 are now and then placed upon an organ, influence the cell work quite 

 specifically. 



The activity of the pancreas is not dependent upon the acid content 

 alone of the food as it reaches the duodenum. It has been found that fats, 

 likewise, have an effect. We have already seen that such food diminishes 

 the amount of gastric juice secreted. The secretion of the pancreatic 

 juice cannot then, as in the case of meats, be influenced by an increased 

 secretion of hydrochloric acid. Fats, on the contrary, stimulate directly 

 the secretion of pancreatic juice. This may be shown by means of a dog 

 provided with both gastric and intestinal fistulas. 1 If after waiting until 

 there is practically no gastric secretion, olive oil is allowed to flow into 

 the stomach, then the slight amount of gastric juice secreted will have an 

 alkaline reaction. At the same time there will be a marked increase in the 

 amount of pancreatic juice. It is questionable whether the fats, and the 

 soaps produced from them, have the same point of attack as the hydro- 

 chloric acid. 2 



It has proved very difficult to ascertain whether the secretion of the pan- 

 creas is influenced by the same chemical substances as that of the stomach. 

 This could be answered satisfactorily only when there was no opportunity 

 given for the hydrochloric acid itself to exert a stimulation. Under such 



1 N. Damaskin: Verhandl. Gesellsch. russ. Aerzte, St. Petersburg (1896). 

 a B. P. Babkine: Arch, des Sciences biol. 11, No. 3 (1905). 



