478 DIGESTION 



stomach, as it has been aptly called. The diminution in tonus and 

 hunger contractions in these various ways is accompanied by a diminu- 

 tion in the hunger pains. 



Afferent nerve stimulation affecting the hunger contractions may also 

 originate in the stomach mucosa itself, as has been shown in the case of Carl- 

 son's patient by introducing the various substances to be tested througli 

 a tube into the stomach. A glassful of cold water introduced in this 

 way inhibits the tonus and the hunger contractions for from three to five 

 minutes unless these are severe, this inhibition being followed by no 

 augmentation either of the tonus or of contractions. Ice-cold water has 

 a greater effect than water at body temperature. This result is some- 

 what different from that which most men experience as the result of 

 drinking a glass of cold water. 



Weak acids of strengths varying up to that found present in the 

 gastric juice itself 0.5 per cent cause a marked inhibition of the 

 hunger movements, but this inhibition does not persist until all the acid 

 has escaped from the stomach or been neutralized, which explains why 

 hunger contractions should still occur when an acid secretion is present 

 in the stomach, as in starvation. Normal gastric juice itself produces 

 an inhibition, which is no doubt dependent upon the acid which it con- 

 tains, and it is probable that, at the same time that it leads to inhibition 

 of the hunger contractions, the acid initiates peristalsis of the pyloric 

 region (see page 453). Weak alkaline solutions have no greater effect on 

 the hunger contractions than an equal volume of water. Weak solu- 

 tions of local anesthetics, such as phenol or chloretone, are without effect. 



With regard to alcoholic beverages interesting results were obtained. 

 Wine, beer, brandy, and diluted pure alcohol inhibit both the tonus and 

 the contractions. The duration of this inhibition varies directly with the 

 quantity of the beverage introduced into the stomach and with its alco- 

 hol percentage. These observations are apparently not in harmony with 

 the experience of most men that the taking of alcoholic beverages serves 

 to awaken or increase the appetite, the difference being no doubt due to 

 the fact that appetite and hunger contractions of the stomach are not 

 dependent on each other, appetite being, as we have seen, a complex 

 psychic affair, whereas the hunger contractions depend upon a local 

 mechanism in the stomach wall itself. 



As the inhibition produced in one or other of these ways passes off, 

 the hunger contractions are resumed at their previous intensity and not 

 in an augmented form. From the promptness of the inhibition, it would 

 appear that the stomach contractions are affected, not reflexly through 

 the central nervous system or by changes in the chemical composition 

 of the blood, but by a direct action on the neuromuscular mechanism 



