236 SOCIAL LIFE IN THE INSECT WORLD 



A loud noise stifles a feeble note and prevents it from 

 being heard ; a brilliant light eclipses a feeble glimmer. 

 Heavy v^aves overcome and obliterate ripples. In the 

 two cases cited we have waves of the same nature. But 

 a clap of thunder does not diminish the feeblest jet of 

 light; the dazzling glory of the sun will not muffle the 

 slightest sound. Of different natures, light and sound do 

 not mutually interact. 



My experiment with spike-lavender, naphthaline, and 

 other odours seems to prove that odour proceeds from 

 two sources. For emission substitute undulation, and 

 the problem of the Great Peacock moth is explained. 

 Without any material emanation a luminous point shakes 

 the ether with its vibrations and fills with light a sphere 

 of indefinite magnitude. So, or in some such manner, 

 must the warning effluvium of the mother Oak Eggar 

 operate. The moth does not emit molecules ; but some- 

 thing about it vibrates, causing waves capable of propa- 

 gation to distances incompatible with an actual diffusion 

 of matter. 



From this point of view, smell would have two 

 domains — that of particles dissolved in the air and that 

 of etheric waves.^ The former domain alone is known 



* The difficult}' in conceiving this theory lies in the fact that the 

 waves travel in straight lines. On the other hand, matter in a state 

 of degradation may expel particles highly energised and of enormous 

 velocity. Most antennas arc covered with hairs of inconceivable 

 fineness ; others may contain cavities of almost infinite minuteness. 

 Is it not thinkable that they are able to detect, in the gaseous 

 atmosphere, floating particles that are not gaseous ? This would not 

 prevent the specialisation of antennae as mere feelers in some insects 

 and crustaceans. The difficulty of such a supposition lies in the 

 fact of discrimination ; but if we did not possess a sense of taste 

 or smell discrimination would seem mconceivable in their case 

 also.— [Trans. 



