TORPIDITY. 71 



of temperature, and reach a supply of food, the power of 

 becoming torpid would be useless, if bestowed on them, 

 although highly beneficial to quadrupeds, that are impa- 

 tient of cold, and cannot migrate lo places whei'e there is a 

 supply of food. This mode of reasoning, however, is faulty, 

 since we employ our pretended knowledge of final causes, 

 to ascertain the limits of the operations of nature . Besides, 

 there are many animals, as we have seen in the class Marti- 

 malia, which become torpid, and a similar state is well 

 known to prevail among the reptiles. As birds, in the scale 

 of being, hold a middle rank between these two classes, being 

 superior to the reptiles, and inferior to the mammalia, we 

 have some reason to expect instances of torpidity to occur 

 among the feathered tribes. 



These remarks have for their object, to prepare the mind 

 for discussing the merits of the question, by the removal of 

 presumptions and prejudices, as we fear preconceived opi- 

 nions have already exercised too much influence. 



In treating of the migrations of the swallow, we endea- 

 voured to point out their winter residence, and even traced 

 them into Africa. We are not however prepared to assert, 

 that in every season all these birds leave this country. If 

 they remain, in what condition are they found ? 



Many naturalists, such as Klein, Linnaeus, and others, 

 have believed in the submersion of swallows during winter 

 in lakes and rivers. They have supposed, that they de- 

 scend to the bottom, and continue there until the following 

 spring. All the statements which we have yet had an op- 

 portunity of consulting, appear either as boyish recollections 

 or hearsay testimony ; and although naturalists have been 

 eagerly waiting for an opportunity of obtaining swallows 

 from their subaqueous retreacs, for the last fifty years, they 

 have hitherto been disappointed. Indeed, the evidence in 

 support of such voluntary submersion, would require to be 



