The Life of the Caterpillar 



Sound is likewise out of the question. The 

 great fat Moth, capable of sending a sum- 

 mons to such a distance, is mute eVen to the 

 most acute hearing. It is just possible that 

 she possesses delicate vibrations, passionate 

 quivers, which might perhaps be perceptible 

 with the aid of an extremely sensitive micro- 

 phone; but remember that the visitors have 

 to be informed at considerable distances, 

 thousands of yards away. Under these con- 

 ditions, we cannot waste time thinking of 

 acoustics. .That would be to set silence the 

 task of waking the surrounding air. 



There remains the sense of smell. In the 

 domain of our senses, scent, better than any- 

 thing else, would more or less explain the on- 

 rush of the Moths, even though they do not 

 find the bait that allures them until after a 

 certain amount of hesitation. Are there, in 

 point of fact, effluvia similar to what we call 

 odour, effluvia of extreme subtlety, absolutely 

 imperceptible to ourselves and yet capable of 

 impressing a sense of smell better-endowed 

 than ours ? There is a very simple experiment 

 to be made. It is a question of masking those 

 effluvia, of stifling them under a powerful and 

 persistent odour, which masters the olfactory 

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