308 INSECT TRANSFORMATIONS. 



a few weeks, at another several months in that 

 state.'* 



But though we admit all these facts, which are 

 known to every naturalist, and too well ascertained to 

 be denied, we submit that the inference of evaporation 

 being the exclusive effect, is, upon the whole, inad- 

 missible. Reaumur, though he does not absolutely 

 state his belief in such an inference, shows by his rea- 

 soning that he was strongly disposed to adopt notions 

 closely bordering upon it. The theoretical doctrine, 

 it may be perceived, takes for granted that evapora- 

 tion is the only result of heat ; overlooking the no less 

 obvious effect of expansion, besides the disposition it 

 produces in chemical principles to combine or be de- 

 composed. But these are only some of its inanimate 

 results, which would occur upon material objects inde- 

 pendently of life; whereas in living bodies, what may 

 be called chemical changes are frequently very differ- 

 ent from what can be effected out of the living body, 

 and consequently we cannot trace all the effects pro- 

 duced by heat in the two great internal processes of 

 secretion and consolidation. In detailing, therefore, 

 the interesting experiments of Reaumur on pupa?, which 

 he subjected to different degrees of heat and cold, we 

 shall not adopt his inferences respecting evaporation 

 The accuracy of the experiments themselves is un 

 questionable. 



Reasoning from some of the facts above stated, 

 Rfaumur thought it might be possible to hasten or 

 retard the exclusion of insects from their pupa?, in 

 the same way as some flowers are forced to blow 

 early, and others kept back Trom blowing at their due 

 season; and he commenced a series of experiments to 

 ascertain the facts. In January 1734, he accordingly 

 placed a great number of the chrysalides of moths 

 and butterflies of various species in one of the royal 



* Intr. iii, 263. 



