194 PHOSPHORESCENCE. 



ther research, I cannot do otherwise than repro- 

 duce here the theory I published for the first time 

 in 1858. 



In the glowworm, the luminosity can be traced 

 directly to the instinct of the insect through what 

 are termed the correlative forces, electricity and 

 nervous force. We find the phosphorescent 

 organ of a greasy nature, a bad conductor of elec- 

 tricity, under the dependence of the nerves, which 

 in their turn depend upon the instinct. In the 

 Fireflies there exist similar organs, destined by 

 nature to produce light ; and, as anatomical science 

 progresses, the same will doubtless be found in 

 those myriads of inferior organisms endowed with 

 phosphorescent properties. Indeed, Ehrenberg 

 has already described what he takes to be the 

 phosphoric organ in Noctiluca miliaris and Photo- 

 charis cyrrigera. 



A given amount of electricity will always pro- 

 duce an equivalent proportion of light when 

 passing through a bad conductor ; and a certain 

 amount of nervous force, acting through the 

 nerves, is capable of producing an equivalent 

 amount of electricity ; finally, it is doubtless true 

 that instinct is correlative with what are called 

 the other modes of force. 



It will be objected, perhaps, that the luminous 

 substance extracted from the body of a Lampyris 

 shines for some time after the death of the insect ; 



