OF FOOD AND FIUNGER. 211 



this state, but by whatever affects also the sensibility to this state, 

 arul therefore be subject to the common laws of sensation. 

 Hence uncivilized tribes enable themselves to traverse large 

 tracts without food by swallowing pills containing tobacco or 

 opium. Thus, the state of the stomach remaining the same, 

 hunger may diminish from the occurrence of other sensations 

 which attract our attention more forcibly, by passions of the 

 mind, &c. ; as is exactly the case with all other sensations, even 

 with those that are morbid. Under strong attention of the 

 mind either to pursuits of intellect or passion, to delightful or 

 painful sensation, all other sensations cease to be felt, although 

 really violent; and frequently, from being unattended to, do 

 not recur. Passions, however, may affect hunger, not only by 

 increasing or diminishing the sensibility to the state of the 

 stomach, but by increasing or decreasing this state the cause 

 of the sensation. 



(B) As hunger appears to depend upon the local condition of 

 the stomach, &c. so does thirst more evidently upon that of the 

 mouth and fauces. Every consideration renders it probable that 

 thirst is the sensation of the absence of moisture in the parts in 

 which it is seated. Whatever produces this, either by causing 

 the fluids of the mouth and fauces to be secreted in small quan- 

 tities or of great viscidity, or by carrying off the fluid when 

 secreted, produces thirst ; and vice versa. To be dry means 

 to be thirsty, because the state is removed by directly wetting 

 the parts, or by supplying the system with fluid that they may be 

 moistened by their own secretions. Being a sensation, the same 

 may be repeated in regard to it as was observed respecting 

 hunger. 



(C) " Most of those," says the Father of Physic, " who nei- 

 ther eat nor drink for seven days, die within that period ; and 

 if they survive and take nourishment, still the previous fast- 

 ing proves fatal." * A girl, however, able to eat and drink and 



* Hippocrates, De carnibus. S. iii. 



p 2 



