On Hyhernalion. 77 



respiratory organs ceases. He could perceive no motion 

 with a microscope, in the flanks of a bat when the ther- 

 mometer was at 43^. Sir John Hunter introduced worms 

 &c. into the stomachs ofiizards, and on examination during 

 the winter found the food unchanged; those that were 

 kept until spring voided it unchanged, thus clearly proving 

 the total suspension of the digestive functions. 



In this stale all sensation appears to be lost, and one 

 function of life alone seems to ren)ain, that is, circulation. 

 Limbs have been broken, and wounds made in animals with 

 every appearance of insensibility. It has been proved 

 that a confined circulation is carried on through the heart 

 and the larger veins and arteries. 



Mr. Carlisle states "that all hybernating mammalia 

 possess a peculiar structure of the heart and its princi- 

 pal veins; the superior cava divides into two trunks, the 

 left passing ovsr the left auricle of the heart opens into the 

 inferior part of the right auricle." 



Spallanzani says — 



" 1 have often opened Newts, Frogs, Toads, and Lizards, 

 when torpid frj/m cold, and apparently dead ; and I have 

 found that the blood did not circulate in the limbs, while it 

 continued to circulate in the large vessels, although the 

 circulation was languid. II a greater degree of cold has 

 penetrated the solids, if it has coagulated the blood, then 

 it is certain the animals perish," — Spallanzani, p. 269. 



While examining this subject it is necessary for us to 

 guard against the similarity of suspended animation and 

 hyhernalion. Spallanzani resuscitated animalculae after 

 having been in a dry slate for 27 years, by adding water to 

 them. In this case air was not essential, nor in hyberna- 

 tion do we find it absolutely so. Spallanzani found that 

 torpid bats lived seven minutes in an exhausted receiver, 

 while another bat died in three minutes. In another ex- 

 periment a bird and rat did not live one minute in carbon- 

 ic acid gas, yet a torpid marmot remained an hour, and 

 then recovered on being exposed to the warm air. 



Gen. Davis in the Lin. Soc. Transactions, has given us a 

 description of a torpid Dipus Canadensis, which was com- 

 pletely deprived of the benefit of air ; he says, 



" It was discovered enclosed in a ball of clay, about the 

 size of a cricket-ball, nearly an inch in thickness, perfectly 



