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 brilhant 
light without any sensible heat ; and that this hght 
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, 1s 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 hght of Noctiluca, 
Pyrosoma, or Lampyride 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, “ 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 
