30 STUDIES IX DIGESTION 



in extractives, to excite a secretion by chemical 

 means even when the appetite is deficient. Next 

 are put on the table the lighter and more digestible 

 fish and poultry. Then comes the roast or boiled 

 beef, the item which will tax most the power of the 

 gastric juice to deal with it. The courses which 

 follow do not depend so much on gastric as on 

 pancreatic digestion. 



Pawlow and his fellow-workers have shown further 

 that the quantity of gastric juice and, especially, the 

 amount of pepsin that it contains bear a remarkable 

 relationship to the nature of the diet. A meat diet 

 calls forth the most powerful secretion, and a milk 

 diet the weakest. 



When we remember that ferments such as pepsin 

 are highly complex and, so to speak, very expensive 

 bodies, it becomes clear why weakly people, con- 

 valescents, fever patients, and dyspeptics may do 

 very much better on a milk diet, which makes small 

 demands on the pepsin, and why they find meat 

 unappetizing and indigestible, seeing that they cannot 

 afford to provide for its efficient disintegration. 



Let us now look at the effects of those few simple 

 remedies, the bitters, alkalies, acids, and alcoholic 

 preparations which every practitioner must occasionally 

 prescribe. Not one of these substances, when intro- 

 duced by Pawlow's fistula directly into the stomach, 

 excites any greater flow of gastric juice than does 

 plain cold water. Some of them are actually harmful 

 in the stomach. Alcohol and bitters, if present in 

 any quantity, diminish the activity of the gastric 

 ferments ; alkalies, if enough is given to neutralize 



