109 



11. The organ of Feeling is the skin in general, with 

 which innumerable nervous papillae are interwoven, 

 which being moved by the slightest touch of other 

 bodies, convey that motion to the brain. But these 

 papilla; abound in all the extremities, particularly the 

 palms of the hand and the tips of the fingers. And 

 hence it is that the sense of feeling is far more exquisite 

 in those than in other parts. 



t 



12. Nearly allied to the senses are the natural ap- 

 petites, particularly Hunger and Thirst. The usual 

 way of accounting for them is this: when the food, 

 now reduced to a pulp, is expressed out of the stomach, 

 it is of course contracted by its muscular coat, this 

 causes the inner coat to lie in folds, which by means of 

 the peristaltic motion, rubbing lightly on each other, 

 occasion the uneasy sensation which we term hunger. 



, This is felt first in the upper orifice which is first eva- 

 cuated ; but as by degrees the rest of the contents are 

 expelled, this rubbing of the membranes on each other 

 spreads over the whole stomach, and renders our 

 hunger more urgent. 



This uneasy sensation is increased by the acidity 

 which the blood in the arteries cf the stomach contracts 

 through long abstinence, its soft balsamic parts having 

 beei: all drawn off; likewise its velocity is considerably 

 augmented, when we have not eaten for some time. 



Hence it is, that hunger, if it continues long, will 

 occasion a violent fever ; that young persons, and 

 those who labour hard, or are of a bilious constitution, 

 are soonest hungry; whereas those whose humours 

 are thick and viscid, are not so soon incommoded 

 therewith. 



13. Hot vapours ascending from the stomach, and 

 drying thu % throat tind mouth, are supposed to be the 

 occasion of that uneasy sensation which we term 

 Thirst. 



1 say, are supposed. For I apprehend nothing can 

 be known with any certainty upon the head. In like 



