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 hight ; 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 nuliaris and Photo- 
charis cyrrigera. 
A given amount of electricity will always pro- 
duce an equivalent proportion of leht 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 lumimous 
substance extracted from the body of a Lampyris 
shines for some time after the death of the insect ; 
