'276 MIGRATION OF ANIMALS. 



who adopted this opinion. He informs us, that swallows are 

 found in great clusters at the bottoms of the northern lakes, 

 with mouth to mouth, wing to wing, foot to foot, and that in 

 autumn they creep down the reeds to their subterraneous re- 

 treats. " That the good archbishop," Mr. Pennant archly 

 remarks, " did not want credulity in other instances, appears 

 from this, that, after having stocked the bottoms of the lakes 

 with birds, he stores the clouds with mice, which sometimes 

 fall in plentiful showers on Norway and the neighboring 

 countries ! " Klein has endeavored to support the notion 

 that swallows lie under the water during the winter, and gives 

 the following account of their manner of retiring, which he 

 collected from some countrymen. They asserted, he tells us, 

 that the swallows sometimes assembled in numbers on a reed 

 till it broke and sunk them to the bottom ; that their immer- 

 sion was preceded by a kind of dirge, which lasted more 

 than a quarter of an hour ; that others united, laid hold of a 

 straw with their bills, and plunged down in society ; that oth- 

 ers, by clinging together with their feet, formed a large mass, 

 and in this manner committed themselves to the deep. 



Two reasons seem to render this supposed submersion of 

 swallows impossible. In the first place, no land animul can 

 exist so long without some degree of respiration. The otter, 

 the seal, and water-fowls of all kinds, when confined under 

 the ice, or entangled in nets, soon perish ; yet it is well 

 known, that animals of this kind can remain much longer 

 under water than those which are destitute of that peculiar 

 structure of the heart which is necessary for any considerable 

 residence beneath that penetrating element. Mr. John Hun- 

 ter, in a letter to Mr. Pennant, informs us, " That he had dis- 

 sected many swallows, but found nothing in them different 

 from other birds as to the organs of respiration ; that all those 

 animals which he had dissected of the class that sleep during 

 winter, such as lizards, frogs, &/c., had a very different con- 

 formation as to these organs ; that all those animals, he be- 

 lieves, do breathe in their torpid state ; and, as far as his ex- 

 perience reaches, he knows they do ; and that, therefore, he 

 esteems it a very wild opinion, that terrestrial animals can 

 remain any long time under water without drowning." An- 

 other argument against their submersion arises from the 

 specific gravity of the animals themselves. Of all birds, th< 

 swallow tribes are perhaps the lightest. Their plumage, an 

 the comparative smallness of their weight, indicate that n- 

 tare destined them to be almost perpetually on the wing 



