The Sense of Smell 



an odour, as our physiology understands the 

 word? I cannot bring myself to believe it. 



The Dog smells the truffle by sniffing the 

 earth, quite close to the tuber; he finds his 

 master at great distances by consulting the 

 scent of his footprints. But is he able to dis- 

 cover the truffle hundreds of yards away, 

 miles away? Can he join his master in the 

 complete absence of a trail? Certainly not. 

 For all his fineness of scent, the Dog is in- 

 capable of such a feat, which is performed, 

 however by the Moth, who is put off neither 

 by distance nor by the lack of any traces out 

 of doors of the female hatched on my table. 



It is a recognized fact that smell, ordinary 

 smell, the smell that affects our nostrils, con- 

 sists of molecules emanating from the scented 

 body. The odorous matter dissolves and is 

 diffused throughout the air by communicating 

 to the air its aroma, even as sugar dissolves 

 and is diffused in water by communicating to 

 the water its sweetness. Smell and taste 

 touch each other at some points ; in both cases 

 there is a contact between the material parti- 

 cles that give the impression and the sensitive 

 papillae that receive it. 



Nothing can be simpler or clearer than that 



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