140 PHOSPHORIC INSECTS. 



cussion of theoretical points ; I must, however, 

 expose a few facts. 



Matteucci himself observes that glow-worms 

 possess a substance which gives forth a brilliant 

 light without any sensible heat ; and that this light 

 is visible after the animal has been torn to pieces ; 

 that it persists for some time after death. 



Those animals which furnish us with examples 

 of rapid and energetic combustion, such as birds, 

 by their respiration, possess also a high degree of 

 animal heat, when compared with animals in which 

 respiration is less energetic. With reptiles, where 

 combustion, due to respiration, is comparatively 

 incomplete, we find on the contrary, an animal 

 heat of a low degree, dependent upon the tem- 

 perature of the place they inhabit. In accordance 

 with this observation, if the light of Noctiluca, 

 Pyrosoma, or Lampyridce was owing to combus- 

 tion, their animal heat would be considerably 

 higher. Experiment, however, shows us the con- 

 trary. 



According to Matteucci, also, the phosphorescent 

 substance, when extracted from the insect and 

 placed in hydrogen gas or carbonic acid, ee ceases 

 to shine in thirty or forty minutes." Thirty or 

 forty minutes is a very long time indeed, for a 

 combustion to continue in gases that are devoid of 

 the faculty of supporting it. As this experiment 

 was very carefully verified by the author, we can 



