cxcu * LIFE OF WILSON. 



servation 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 determine, 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 Alexander Wilson, both 

 of whom have recorded their testimony, in the most positive 

 manner, against torpidity. 



The " Memoir on the Migration and Torpidity of Swallows," 

 wherein Dr. Barton was confident he should be able to convince 

 every candid philosopher of the truth of his hypothesis con- 

 cerning these birds, never issued from the press, although so 

 publicly announced. And who will venture to say that he did 

 not, by this suppression, manifest his discretion? When Wil- 

 son's volume, wherein the swallows are given, appeared, it is 

 probable that the author of the " Fragments" was made sensi- 

 ble that he had been writing upon subjects of which he had lit- 

 tle personal knowledge; and therefore he wisely relinquished 

 the task of instructing philosophers, in these matters, to those 

 more capable than himself of such discussions. 



Naturalists have not been sufficiently precise when they have 

 had occasion to speak of torpidity. They have employed the 

 term to express that torpor or numbness, which is induced by a 

 sudden change from heat to cold, such as is annually experienced 

 in our climate in the month of March, and which frequently 

 affects swallows to so great a degree as to render them incapa- 

 ble of flight. From the number of instances on record of these 

 birds having been found in this state, the presumption has been 

 that they were capable of passing into a state of torpidity, simi- 

 lar to that of the Marmots, and other hybernating animals. 



Smellie, though an advocate for migration, yet admits that 

 swallows may become torpid. " That swallows," says he, " in 

 the winter months, have sometimes, though very rarely, been 



