CHAP. 72.—THE LUNGS: IN WHAT ANIMALS THEY ARE THE LARGEST, AND IN WHAT THE SMALLEST. ANIMALS WHICH HAVE NOTHING BUT LUNGS IN THE INTERIOR OF THE BODY. CAUSES WHICH PRODUCE EXTRAORDINARY SWIFTNESS IN ANIMALS.
Beneath the heart are the lungs, the laboratory in which the respiration is prepared. The use of these, is to draw in the air and then expel it; for which purpose their substance is of a spongy nature, and filled with cavernous holes. Some few among the aquatic animals have lungs, as we have already stated;280 and among the rest of those which are oviparous, they are small, of a fungous nature, and containing no blood; hence it is, that these animals do not experience thirst. It is for the same reason also, that frogs and seals are able to remain so long under water. The tortoise, too, although it has lungs of remarkable size, and extending throughout the whole of the shell, is also equally destitute of blood. The smaller the lungs are in proportion to the body, the greater is the swiftness of the animal. It is in the chameleon that the lungs are the largest in proportion to the body; in which, in fact, it has no other viscera at all.281