An Unknown Sense 



vestigate, they anticipate the impression. 

 The impression of what? If it were really 

 an impression of smell, repose would serve 

 them better than a perpetual quivering. 



But there is more to be said : the olfactory 

 sense goes for nothing when there is no 

 smell. Now I have tested the Grey Worm 

 for myself; I have given it to young nostrils 

 to sniff, nostrils much more sensitive than 

 mine : not one of us has perceived the faint- 

 est trace of smell in the caterpillar. When 

 the Dog, famed for his scent, becomes aware 

 of the truffle underground, he is guided by 

 the tuber's savour, which is highly appre- 

 ciable by ourselves, even through the thick- 

 ness of the soil. I admit that the Dog has 

 a more subtle sense of smell than we have: 

 it is exercised at greater distances, it receives 

 more vivid and lasting impressions; never- 

 theless, it is impressed by odorous effluvia 

 which becomes perceptible to our own nos- 

 trils under the proper conditions of prox- 

 imity. 



I will allow the Ammophila, if you like, a 

 scent as delicate as that of the Dog, more 

 delicate even; but still a smell is needed; and 

 I ask myself how that which is inodorous at 

 the very entrance to our nostrils can be odor- 

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