OF DIGESTION. 161 



we live, where regular hours are appointed for meals, so that one 

 shall succeed before the interval after the preceding shall have been 

 so long as to produce pain, scarcely any one knows what hunger 

 really is, except by some self-inflicted abstinence. Yet though 

 unaccustomed to be felt by us, there is an unpleasant sensation 

 produced by want of food, amounting at first only to a feeling of 

 emptiness, lassitude, and indescribable uneasiness, but gradually 

 getting worse until it end in actual pain, as if the inward parts were 

 all on fire. There was a time when it was thought that the internal 

 surfaces of the empty stomach rubbing against one another pro- 

 duced hunger, and hence arose the vulgar phrase of " taking the 

 wrinkles out of your stomach," by satisfying the appetite ; but that 

 is too mechanical an explanation. If the sensation proceeded 

 merely from such rubbing of the coats of the stomach, food swal- 

 lowed would be more likely to aggravate than to assuage the gnaw- 

 ing of hunger ; to excite the action of the stomach would be to 

 excite the appetite ; and an irritable stomach would be attended 

 with an insatiable desire for food. Something more than mere 

 emptiness is required to produce hunger. By some of the ancients, 

 hunger was referred to the weight of the liver dragging down the 

 empty stomach, forgetting that the liver is as heavy, and will drag 

 as much when the stomach is full as when it is empty. By others, 

 with more probability, it is supposed to proceed from the action of 

 the gastric fluid on the nerves in the coats of the stomach. Hun- 

 ger is, like thirst, a sense placed as a safeguard calling for what is 

 necessary for the system, and depending on the general state of the 

 body. Morbid craving may proceed from many causes ; a tape- 

 worm in the bowels has occasioned voracious appetite, and ardent 

 spirits and high ^seasoning excite it even when the stomach is full ; 

 but natural hunger has always a reference to the wants of the gene- 

 ral system. 



THIRST. 



Thirst is a sensation seated in the tongue, throat, gullet, and 

 stomach. It depends on the state of the membrane which lines 

 these parts, and of the fluids which naturally moisten it, and may 

 arise either from a deficiency of that fluid, or from an acrid state of 

 it. It would appear to be placed as a monitor calling for the dilu- 

 tion of the fluids by drink, when they have been exhausted by 

 perspiration and the fatigue of the body, or when the contents of 

 the stomach require to be made more fluid, the more easily to suffer 



