OF HUNGER AND THIRST. 285 



snake, and other cold-blooded animals, take food 

 after intervals of days or weeks. A horse, on the 

 contrary, is always feeding. His stomach, at most, 

 contains about four gallons, yet throw before him 

 a truss of tares or lucerne, and he will eat contin- 

 ually. The emptying of the stomach cannot 

 therefore be the cause of hunger. 



The natural appetite is a sensation related to 

 the general condition of the system, and not sim- 

 ply referable to the state of the stomach ; neither 

 to its action, nor its emptiness, nor the acidity of 

 its contents ; nor in a starved creature will a full 

 stomach satisfy the desire of food. Under the 

 same impulse which makes us swallow, the rumi- 

 nating animal draws the morsel from its own 

 stomach. 



Hunger is well illustrated by thirst. Suppose 

 we take the definition of thirst — that it is a sense 

 of dryness and constriction in the back part of the 

 mouth and fauces ; the moistening nf thpse parts 

 will not allay thirst after much fatigue or during 

 fever. In making a long speech, if a man's mouth 

 is parched, and the dryness is merely from speak- 

 ing, it will be relieved by moistening ; but if it 

 comes from the feverish anxiety and excitement 

 attending a public exhibition, his thirst will not be 

 30 removed. The question, as it regards thirst, 

 was brought to a demonstration by the following 

 circumstance : — A man having a wound low down 

 in his throat, was tortured with thirst ; but no 

 quantity of fluid passing through his mouth and 



