CXCIl 
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 
