ORGANIZATIONOFREPTILES. 27 



weather at Christmas. During hybernation, Reptiles can undergo an intense 

 degree of cold; we have seen Frogs frozen in a solid lump of ice, which being 

 melted, the anunals regained their activity; and Du Fay observed the same thing 

 of Water-newts.* Other animals of a higher grade hybernate in the colder parts 

 of our country, as the Wood-chuck, (Arctomys monax,) and many kinds of Bat, 

 (Vespertilio,) but in none is the sleep so profound, the suspension of the faculties 

 so complete; the pulmonary respiration continues, though diminished in frequency, 

 yet enough to support the life of the animal. It follows from these remarks, that 

 Reptiles belong essentially to warm, or at least to temperate, climates; none are 

 found in the extreme cold regions either of the north or south; there they could 

 not retain the necessary degree of activity to seek their food or reproduce their 

 species. Reptiles can withstand the operation of great heat, as well as of intense 

 cold; they thrive under our hottest summer suns, and are found even in some 

 springs of a greatly elevated temperature. 



Connected with the mode of life and the nutritive functions of Reptiles, is 

 the remarkable phenomenon of the restoration of parts when injured, or the 

 complete reproduction of organs which have been destroyed. This reproductive 

 power is very active in the inferior order of animals, and the lower we descend 

 in the scale the more remarkable are its manifestations. In Crabs and Lobsters, 

 limbs are readily restored, and in snails, the entire head has been reproduced; 

 the head of a Hydra may be split in several places, and each subdivision will 

 become a new head. In the higher classes, wounds may be healed, injuries 

 repaired, but an organ once destroyed, cannot be reproduced; and even in Rep- 

 tiles of a higher degree of life, as in the Chelonia, reproduction of parts is never 

 complete as in those of a lower grade of organization, as in the Salamander. 

 Pliny first observed that some Reptiles reproduced the tail; and Bonnett and 

 Blumenbach:]: have confirmed this remark, and made many curious experiments 

 on the reproductive power of Reptiles. They removed the limbs of a Water- 



* Mem. de I'Acad. des Sciences, 1729, p. 144. 



t CEuvres d'Histoire Naturelle, torn. v. t Speclm. Phys., p. 31. 



