164 THE HOUSE I LIVE IN. 



which has a communication with the inside of 

 the nose. 



3. There are also cavities in the forehead, 

 at the top of the nose, between the eyes, 

 which communicate, in like manner, with the 

 cavity of the nose. 



Over this extensive internal surface, viz. the 

 whole inside of the nose, the surface of the 

 projections or shelves, and the inside of the 

 cavities in the cheek bone and forehead, a fine 

 delicate membrane is spread ; and over a great 

 part of this membrane, little nerves are dis- 

 tributed, by means of which we smell. For I 

 wish to say again, once for all, that we cannot 

 have feeling or sensation, in the eye, in the ear, 

 in the nose, or anywhere else, without the aid of 

 these little branches of the brain, called nerves. 

 And it helps us about smelling, that the parti- 

 cles of bodies in the air \ve breathe, are diffused 

 over such a large surface as I have mentioned. 



I have more than intimated that in a natural 

 state of the organ of smell, it could detect all 

 substances which were likely to prove inju- 

 rious. This, though very probable, cannot be 

 fully proved. Other animals, we know, can in 

 general tell what will injure them, by its smell ; 



