286 FACULTIES OF BIRDS. 
The most recent authority which we have met 
with upon the subject is that of Baron Cuvier, who 
asserts of the bank-swallow (Hirundo riparia, Puiny), 
as “ well authenticated, that it falls into a lethargic 
state during winter, and even that it passes that 
season at the bottom of marshy waters.” It would 
have been well if he had at least referred us to 
some of these authenticated accounts; for we have 
been unable to trace anything more satisfactory 
than what we have already mentioned. 
We deem it unnecessary to enter at much length 
upon a refutation of these opinions, as it must be 
obvious that it is physiologically impossible for a 
swallow or any other bird to live many minutes, 
much less for months, under water. The frog and 
other amphibious animals which do hybernate under 
water have a peculiar formation of the heart which 
enables them to do so, and which is not thus form- 
ed in swallows. ‘‘ Though entirely satisfied,” says 
Pennant, “in our own mind of the impossibility of 
these relations, yet desirous of strengthening our 
opinion with some better authority, we applied to 
that able anatomist, Mr. John Hunter, who was so 
obliging to inform us that he had dissected many 
swallows, but found nothing in them different from 
other birds as to the organs of respiration. That 
ali those animals which he had dissected of the 
class that sleep during winter, such as lizards, frogs, 
&c., had a very different conformation as to these 
organs. That all these animals, he believes, do 
breathe in their torpid state; and, as far as his ex- 
perience reaches, he knows they do; and that there 
fore he esteems it a very wild opinion that terres- 
trial animals can remain any long time under water 
without drowning.’’* 
Independently of the established principles of 
physiology, the matter has been experimentally 
* Brit. Zool., ii., 253, 
