( xiii ) 



pid or other state, during the winter-season, seems rather to streugtlien, than to weaken, the argument, that these 

 birds are, in general, migratory birds. If all these birds continued among us, many of them would be found. 

 The labours of one century, or more, in cutting down the timber of the forest, in blowing rocks, in drainmg mill- 

 ponds, and marshes, woidd furnish more than five or six instances (and they not always quite so well authenti- 

 cated as we could wish) of Swallows, &c. beiug found during the winter-season, in a benumbed state. 



§. XXVII. 



The argument derived from the torpid state into which so many of our animals are observed to faU upon the ap- 

 proach of winter, is of less weight than may, at first sight, be imagined. These animals are much less capable of 

 migi-ating than the birds. If they were capable of making long journies to more favom\able climates, I do not doubt 

 they would make them. For I am persuaded, by a variety of experiments and observations which I have made, and 

 may, perhaps, be induced to communicate to the public at some future period, that most of our hybernating ani- 

 mals go with reluctance into this state. I am even of opinion, that the state of torpidity of inami animals is a state 

 of pain and sufferance. This observation, at least, seems to hold good with respect to those animals (and I believe 

 they constitute the gi'eater number of the hybernating animals) which divide the winter between sleeping and wak- 

 ing : which, in other words, under the influence of cold and other causes, fall into a kind of profound sleep, during 

 which the functions of the heart and the lungs are constantly performed ; and even that of the stomach and intes- 

 tines, in some measure, goes on : and during all which time, such animals are sensible to the influence of mecha- 

 nical and other stimuli. This class of hybernating quadrupeds often, during the course of the winter, spontaneously 

 awake from their slumber, take food, and fall into slumber, again. I do not, however, imagine, that animals, which 

 are so torpid as to be incapable of being roused by the application of the most powerful stimuli, can be said to be in a 

 state of pain and sufferance. But I believe, that the number of these coivtinual sleepers is very small, even in the 

 coldest climates. 



§. XXVIII. 



We are certain, that the tdrpid state of many animals is altogether an accidental circumstance: that is, it is not 

 necessary to the species. I will not assert, with my learned and ingenious fiiend, Mr. Fabricius, that it is not natural 

 to, nor coeval with, the species. It would be difficult to prove this position : but the position which I have advanced 

 may be maintained. Animals of the same species have often a very extensive range over the world. Thus, the Ursus 

 Lotor, or Raccoon, extends from Lake-Superior to the West^India-Islands, and the warm parts of South-America. 

 The Opossum has a range not much less extensive. I trace the Rattle-Snake (Crotalus borridu.s) as far north as the 

 Bay of Saguena, on Lake-Huron, and it is Imown in the country of Brasil. In such extensive tracts of country, these 

 animals are exposed to very different degrees of temperature : on the one hand, to a gi-eat alternation of heat and 

 cold ; on the other hand, to a perpetual spring and summer. We ought not, therefore, to expect to find any of 

 them torpid in the whole of this extensive range. In fact, several of those animals which become torpid in the 

 northern parts of our country do not fall into this state in the southern and warmer climates.* As cold, how^ever, 

 is not the only cause of the torpidity of animals, we must not be surprized to find instances of animals becom- 

 ing torpid in climates that are warm. Extreme heat, like extreme cold, seems to predispose the animal system to 

 this state, particularly, perhaps, when there is a deficiency of food. 



§. XXIX. 



We see that quadrupeds and some other animals do occasionally, during severe vnnters, migrate to more southern 

 climates. 1 am assured, that the Bears migrate, in great numbers, every autumn, across the Mississippi, going south 

 (perhaps to the mountains of New-Mexico), in search of a milder climate. In the spring, they return again by 



' See my account of the Di()ui! Americanus, or American Jerboa, in the 4tli Tolame of the Transactions of the American Philosophical Bociety. 



