72 PHILOSOPHY OF ZOOLOGY. 



of the most unexceptionable kind, as there are the strong* 

 est probabilities against the occurrence. Swallows are 

 much lighter than water, and could not sink in clusters, 

 as they are represented to do. If their feathers are pre- 

 viously wetted, to destroy their buoyant power, in what 

 manner can they resist the decomposing effect of six months' 

 maceration in water, and appear in spring as fresh and 

 glossy as those of other birds? Swallows do not moult 

 while they remain with us in an active state, so that if they 

 submerge, they either do not moult at all, or perform the 

 process under water. In the case of the other torpid ani- 

 mals, some vital actions are performed, and a portion of 

 oxigen is consumed ; but in the submersed swallows, re- 

 spiration cannot be performed, and consequently circulation 

 must cease. How, then, is the system able for so many 

 months to resist the destructive influence of its situation, in 

 reference to the abstraction of heat ? We may add, that 

 the other torpid animals, in retiring to their winter slum- 

 bers, consult safety ', while the swallow, in sinking under 

 the water, rushes to the place where the otter and the pike 

 commit their depredations, against which it cannot contend, 

 and from which it has no means of escape. 



These considerations, joined to the circumstance that mi- 

 gration is in ordinary cases practised by the swallow, lead 

 us to doubt the truth of the reports which have been cir- 

 culated on the subject. Amidst the endless resources pf 

 Nature, it may happen that, from some particular circum- 

 stance, migration, with a few, may be impracticable, and 

 these may have been enabled to become torpid. It may 

 likewise have happened, that these birds, taking shelter in 

 holes in the margin of banks, haye fallen into the water, in 

 consequence of their retreat giving way, and that they may 

 have been taken, previous to drowning. The general belief 

 throughout Scotland, that they are occasionally found in a 



