_Miscellanies. 187 
suffering condition ; and the thermometer must have been affected 
by the evaporation of the fluids of the insect. The thermo-multiplier, 
slightly modified, offers the means of repeating these experiments 
without incurring any of the inconveniences above alluded to. As 
the result of our experiments, it must be admitted that insects of 
Sess a temperature of their own, however slightly superior it may be 
in some cases to that of the surrounding medium. Without enlarg- 
ing upon the names of the different insects submitted to our instru- 
ment, or stopping to particularize the effects produced on each indi- 
vidual, it will suffice to say—that we have experimented upon more 
than four hundred indigenous insects, selected from all the different 
classes, and in all the states of metamorphosis in which these animals 
are ever found. The differences of temperature amount in some 
eases to 30°; but all the divisions of the needle were positive ; that 
is to say, in the calorific sense of the insect. 
In comparing the different results obtained in the order of the 
Lepidoptera, we observed a law, which seems worthy of remark ; 
viz. “'The caterpillars always possess a more eles ased temperature 
than the butterflies or the chrysalides.” 
_ Now the respiratory system of insects in oe caterpillar state, is 
auth more developed than that of the same animals metamorphosed — 
_into.chrysalides, or into butterflies ; and we should say from these 
signs, that the insect, in the first period of its life, where its nourish- 
ment is abundant and its growth rapid, converts into carbonic acid a 
much greater quantity of oxygen, than at subsequent periods. It 
follows from admitting these considerations and the law announced, 
‘that the heat of the animal will vary, so to speak, proportionally to 
the quantity of oxygen employed in the act of respiration. 
The theory which attributes animal heat to a slow combustion of 
the blood, appears then to be supported not only by the comparison 
of birds and mammifera, of mammifera and reptiles, which pos- 
Sess a temperature as much more elevated as their respiratory sys- 
tem is more active ; but also by the relation which subsists between 
_ the vivacity of the respiration of certain inseets and their tempera- 
ture. 
There are many bodies which, like insects, give us reason to be- 
cere that they possess a temperature independent of the surrounding 
may be submitted to the trial of the thermo-multiplier. 
Tt Is 3 thus, for example, that we have obtained a deviation of 50° in 
i - into the interior of our apparatus a very small Pinot: of 
