CHAPTER l. IV 



EUNGEB AND APPETITE 



Bunger and appetite are distincl and separate sensations, the former 

 being definitely correlated with contractions of the empty stomach, and I 

 latter, a complex of sensory impressions integrating in the nervous - 

 along with memory impressions of the Bight, taste, and smell of palatable 

 food. Appetite is therefore a highly complex nervous integration, .when 

 hunger is a much simpler process. It is particularly with hunger that 

 we shall concern ourselves at present. 



When a thin-walled rubber balloon of proper size is placed in I 

 stomach and connected l»y a rubber tube with a water, bromoform or 

 chloroform manometer (made of vide irlass tubing 1.5 cm in diami 

 and provided with a suitable float on the free limb) a tracing may be 

 taken of the movements of the stomach. For use on man the caps 

 the balloon should be from 75 to 150 cubic criitini'*. iv | i . thus 



obtained when the balloon is placid in the empty stomach rmal 



person shows four types of wave. Two of these may be discount 

 being due to the arterial pulse and the respiratory movemi The 



third is known as the tonus rhythm, and is caused by tonic contra 

 of the fundus of the stomach of varying amplitude. Tl,.- periods of tonus in- 

 crease during the powerful rhythmic contraction to be immedial 

 described. While these changes in tone are occurring, do Bubjectr 

 sation of hunger is experienced. See Pig. 167. 



The fourth and most significant typ i - iU of powerful rkytkn 



contractions, alternating with periods of quiesc Tl 



tions occupy a period of aboul twenty seconds, and 



upon the tonus rhythm. They gradually ii • in amplitude 



quency; and, in the case of young and vigorou 



pass into a condition of incomplete tetanus, aft.r which they nly 



subside, leaving only a faint tonus rhythm. These rhythmic eontt 



tions are definitely associated with the >f hue 



more marked the more intense th< ition. When tetan - lurs 



the hunger sensation is continuous, but it instantly 

 the tetanus gives place to relaxation Whei tl -tractions are com- 

 paratively feeble, the length of the period during which they occur i* 



471 



