STIMULI OF DIGESTIVE GLANDS 163 



Vegetables are digested in the stomach so far as proteins are 

 concerned, their connective tissue having been previously softened. 

 Their starch and sugar content, and their oils as above. 



The best temperature for digestion is the normal temperature 

 of the interior of the body, or about 100 Fahrenheit. 



Clinical note. The reason for abstaining from ice-water during digestion 



is that the various ferments cannot do their work in a temperature of much less 



than 100 F. (If people will eat ice-cream after dinner they should take it 



slowly, that the whole process of digestion be not too long delayed by the 



necessity of waiting for the temperature to rise again to ioo.) 



Warm foods make less of a demand upon the vitality of the body than 

 cold ones. 



The activity of the digestive glands (like that of all others) is 

 called forth by a stimulus of some sort conveyed to the gland cells 

 by sympathetic nerves. 



In the case of the salivary glands this stimulus is aroused 

 by several things first, by the presence of food in the mouth; 

 second, by the introduction of substances which have an agree- 

 able flavor or odor; third, by movements of the muscles of mas- 

 tication; fourth, by the sensation of nausea; fifth, by the thought 

 of food (which is a psychic stimulus). The salivary secretion is 

 diminished in fevers and wasting diseases, also by certain psychic 

 impressions as fear, anger, anxiety, and the like. Everyone 

 knows the dry mouth of strong emotion, especially if associated 

 with apprehension. 



The gastric glands respond in a similar manner; the presence of 

 food in the stomach causes a strong flow, flavors and odors assist. 

 Small amounts of bitter flavors in food increase it, aromatic 

 substances have the same effect. 



Clinical note. These do not act at once; therefore aromatic or strongly 

 flavored medicines should be given a quarter of an hour or more before meals 

 in order to ensure the best result. 



Water increases the flow. The habit of taking water before 

 meals is a good one, but if taken immediately before the quantity 

 should be small. Alcohol, like the bitters, also stimulates the 

 flow of gastric juice. 



The thought of food causes the psychic flow. Strong desire 

 for food, or appetite, causes a psychic flow of very active juice within 



