LIFE OF AVILSON. cxxvii 



who had so long had the subject of the torpidity of animals under his conside- 

 ration, should have hazarded the assertion contained in the preceding para- 

 graph. Dr. Keeve has certainly read of other birds besides the swallow, the 

 cuckoo, and the woodcock, which are said to have been found in a torpid state. 

 And ought he not to have mentioned these birds '/ 



'■In my 'Fragments of the Natural History of Pennsylvania,' I have men- 

 tioned the common humming-bird ( Trochilus culuhris) as one of those American 

 birds which do occasionally become torpid. 



" In regard to the swallows, I shall say but little at present. I have, at this 

 time, in the press, a memoir on the migration and torpidity of these birds. / 

 am confident that I shall be able to eonvince eoery candid philosopher, that 

 great numbers of sicallows, of different species, do occasionally pass into a state 

 of torpidity, more or less profound, not merely ' in some remote quarter of 

 America,' but in the vicinity of our capital cities, where there are some men 

 of genuine observation and inquiry, and who are as little propense to believe 

 the marvellous in natural history, as any philosophers elsewhere. 



" I do not suppose that all the swallows of North America become torpid. 

 It is my present opinion, and it was my opinion when I published the ' Frag- 

 ments' in 1799, that the swallows, in general, are migratory birds. But sub- 

 sequent and very extensive inquiries have convinced me, that the instances of 

 torpid swallows are much more frequent than I formerly supposed they were ; 

 and that J;here are two species of the genus Hirundo, which are peculiarly dis- 

 posed to pass the brumal season in the cavities of rocks, in the hollows of 

 trees, and in other similar situations, where they have often been found in a 

 soporose state. These species are the Hirundo riparia, or sand swallow j and 

 the H. pelasgia, which we call chimney swallow. There is no fact in orni- 

 thology better established than the fact of the occasional torpidity of these two 

 species of Hirundo !"* 



It is not strange that the " very extensive" inquiries of our learned professor 

 should have had a result so different from those of Wilson, an ornithologist 

 infinitely better qualified than himself to investigate a question of this kind, by 

 his zeal, his capacity, and his experience. Who those men ot genuine observa- 

 tion and inquiry were, who resided in the vicinity of our capital cities, he did 

 not condescend to inform us ; if he had done so, we should be enabled to de- 

 termine, whether or not they were capacitated to give an opinion on a subject, 

 which requires qualifications of a peculiar kind. 



At the time in which the professor wrote the above-cited letter, I know of 

 but two naturalists in the United States whose opinions ought to have any 

 weight on the question before us, and these were William Bartram and Alex- 

 ander Wilson, both of whom have recorded their testimony, in the most posi- 

 tive manner, against torpidity. 



* Tilloch's Philosophical Magazine, vol. 35, p. 241. 



" Naturalists," says Dr. Barton in another place, " have not always been philosophera. 

 The sliyht and superficial manner in which they have examined many of the subjects of 

 their science ; the credulity which has accompanied them in their researches after truth ; 

 and the pi-ecipitaucy with ivhich they have decided upon many questions of importance; are 

 proofs of this assertion." Memoir concerning the fascinating faculty of serpents. 



