142 THE WORK OF THE DIGESTIVE GLANDS. 



which do not excite the gastric glands. On the other hand, by lessening 

 the acidity of the gastric juice we could reduce the activity of the 

 pancreas, and these are matters which might be made use of in various 

 special diseases, or even in some general disturbances of the digestive 

 apparatus. 



No less instructive is a comparison of the results of our experiments 

 upon fat, with the demands of instinct and also with the precepts of 

 dietetics and therapeutics. Everybody knows that fatty foods are 

 heavy, that is, difficult of digestion, and in the case of Aveak stomachs 

 they are usually avoided. We are now in a position to understand this 

 physiologically. The existence of fat in large quantities in the chyme 

 restrains in its own interest the further secretion of gastric juice, and 

 thus impedes the digestion of proteid substances ; consequently, a com- 

 bination of fat and proteid-holding foods is particularly difficult to 

 digest, and can only be borne by those who have good stomachs and 

 keen appetites. The combination of bread and butter is less difficult, 

 as might a priori be inferred from its wide employment. Bread requires 

 for itself, especially when calculated per unit, but little gastric juice 

 and but little acid, while the fat which excites the pancreatic gland 

 ensures a rich production of ferment both for itself and also for the 

 starch and proteid of bread. Fat alone does not count by any means 

 as a heavy food, as may be seen from the fact that large quantities of 

 lard are consumed in certain districts of Russia with impunity. This 

 also is comprehensible, since the inhibitory influence of the fat in this 

 case does not prevent the digestion of any other food-stuff, and is con- 

 ducive to the assimilation of the fat itself. There is no struggle in this 

 case between the several food constituents, and therefore no one of 

 them suffers. In harmony also with daily experience, the physician, in 

 cases of weakness of the stomach, totally excludes fatty food and recom- 

 mends meat of a fat-free kind, for example, game, &c. In pathological 

 cases, however, where an excessive activity of the gastric glands is 

 manifested, fatty food, or fat as emulsion, is prescribed. And here 

 medicine has empirically brought to its aid the restraining action of 

 fat, which we have so strikingly seen in our experiments. 



Amongst all the articles of human food, milk takes a special position, 

 and this is unanimously recognised, both in daily experience and in the 

 practice of medicine. By everybody milk is considered a light food, 

 and is given in cases of weak digestion as well as in a whole series 

 of severe illnesses, for example, in heart and kidney affections. The 

 extreme importance of this substance, a food prepared by nature 

 itself, we can now well understand. There are three properties of 

 milk which secure it an exceptional position. As we already know, 

 in comparison with nitrogenous equivalents of other foods, the weakest 



