The Glow- Worm and Other Beetles 



which the voluntary agency of the insect is 

 without effect. I detach a strip of the 

 epidermis showing one of the luminescent 

 sheets and place it in a glass tube, which I 

 close with a plug of damp wadding, to avoid 

 too rapid an evaporation. Well, this scrap 

 of carcass shines away merrily, although not 

 quite as brilliantly as on the living body. 



Life's aid is now superfluous. The oxi- 

 dizable substance, the luminescent sheet, is 

 in direct communication with the surrounding 

 atmosphere; the flow of oxygen through an 

 air-tube is not necessary; and the luminous 

 emission continues to take place, in the same 

 way as when it is produced by the contact of 

 the air with the real phosphorus of the chem- 

 ists. Let us add that, in aerated water, the 

 luminousness continues as brilliant as in the 

 free air, but that it is extinguished in water 

 deprived of its air by boiling. No better 

 proof could be found of what I have already 

 propounded, namely, that the Glow-worm's 

 light is the effect of a slow oxidization. 



The light is white, calm and soft to the 

 eyes and suggests a spark dropped by the full 

 moon. Despite its splendour, it is a very 

 feeble illuminant. If we move a Glow-worm 

 along a line of print, in perfect darkness, we 

 can easily make out the letters, one by one, 



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