JiXiscellanies. 187 



suffering condition ' "W- .-'' , thermometer must have been affected 

 by the evaporation jids of the insect. The thermo-multiplier, 



slightly modified, offers /iP 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 pos- 

 sess a temperature of their own, bowever slightly superior it may be 

 ii> sonie 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 

 cases 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 j 

 viz. " The caterpillars always possess a more elevated temperature 

 than the butterflies or the chrysalides." 



Now the respiratory system of insects in the caterpillar state, is 

 much more developed than that of the same animals metamorphosed 

 into chrysahdes, 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 raammifera 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 insects and their tempera- 

 ture. 



There are many bodies which, like insects, give us reason to be- 

 lieve that they possess a temperature independent of the surrounding 

 air. These may be submitted to the trial of the thermo-multiplier. 

 It is thus, for example, that we have obtained a deviation of 50° in 

 introducing into the interior of our apparatus a very small piece of 



