LECT. VIII. CONCLUSIONS. 165 



and, as usual, the intermittence first ceased. When I in- 

 troduced air, immediately on the disappearance of the 

 phosphorescence, this phenomena recommenced. In this 

 case, I very distinctly saw all the glow-worms recover the 

 faculty of motion which they had lost ; so that though they 

 had ceased to shine in rarefied air, they were not dead. 

 The same thing occurred on cooling them. 



Conclusions. These facts necessarily lead to the follow- 

 ing conclusions, conclusions which are either entirely new, 

 or more rigorously deduced from experiment, than any that 

 have hitherto been published : 



1st. The phosphorescence of the glow-worm may cease, 

 without the insect being dead. 



2dly. There exists in this insect a matter which evolves 

 light, without any appreciable heat ; and the animal, to 

 manifest this property, does not necessarily require either 

 to be entire, or to possess life. 



3dly. Carbonic acid and hydrogen form a medium in 

 which the phosphorescent matter of the glow-worm ceases 

 to shine after an interval of time, not exceeding thirty or 

 forty minutes, provided that the gases are pure. 



4thly. In oxygen gas, the brilliancy of the phosphores- 

 cent matter is considerably greater than in atmospheric air, 

 and the duration of the phosphorescence is nearly three 

 times as long. This holds good with regard to the luminous 

 segments only, as well as with the entire animal. 



5thly. This phosphorescent matter, placed under condi- 

 tions suitable for the emission of Jight, absorbs a portion of 

 oxygen, which is replaced by an equal volume of carbonic 

 acid. 



6thly. This same substance, when deprived of its faculty 

 of glowing, and then placed in contact with oxygen gas, no 

 longer absorbs oxygen, or produces carbonic acid. 



7thly. Oxygen mixed with either hydrogen or carbonic 



