4^4:8 HYBEIINATION OF INSECTS. 



zero), they could not be made to revive '. But other 

 trials have fully confirmed Lister's observations. My 

 friend Mr. Stickney, before mentioned as the author of 

 a valuable Essay on the Grub (larva of Tipula oleracea) 

 — to ascertain the effect of cold in destroying this insect, 

 exposed some of them to a severe frost, which congealed 

 them into perfect masses of ice. When broken, their 

 whole interior was found to be frozen. Yet several of 

 these resumed their active powers. Bonnet had pre- 

 cisely the same result with the pupae of Pontia Brassicce, 

 which, by exposing to a frost of 14° R. below zero (0° 

 F.), became lumps of ice, and yet produced butterflies''. 

 Indeed, the circumstance that animals of a much more 

 complex organization than insects, namely, serpents and 

 fishes, have been known to revive after being frozen, is 

 sufficient to dispel any doubts on this head. John Hun- 

 ter, though himself unsuccessful in his attempts to re- 

 animate carp and other animals that had been frozen, 

 confesses that the fact itself is so well authenticated as 

 to admit of no question'^. 



On what principle a' faculty so extraordinary and so 

 contrary to our common conceptions of the nature of 

 animal life depends, I shall not attempt to explain. Nor 

 can any thing very satisfactory be advanced with regard 

 to the source of the power which many insects in some 

 states, and almost all in the egg state, have of resisting 

 intense degrees of cold without becoming frozen. It is 

 clear that the usual explanation of the same faculty to a 

 less degree in the wai'm-blooded animals — the constant 

 production of animal heat from the caloric set free in 



* Reaum, ii. 142. '' CEuvrcs, vl. 12. 



' Observations on the Animal Economy, 99. 



