Aristotle On Youth and Old Age,On Life and Death,On Breathing-Part 15

Some animals occupy the water, others live on land, and, that beingso, in the case of those which are very small and bloodless therefrigeration due to the surrounding water or air is sufficient toprevent destruction from this cause. Having little heat, theyrequire little cold to combat it. Hence too such animals are almostall short-lived, for, being small, they have less scope for deflectiontowards either extreme. But some insects are longer-lived thoughbloodless, like all the others), and these have a deep indentationbeneath the waist, in order to secure cooling through the membrane,which there is thinner. They are warmer animals and hence require morerefrigeration, and such are bees (some of which live as long asseven years) and all that make a humming noise, like wasps,cockchafers, and crickets. They make a sound as if of panting by meansof air, for, in the middle section itself, the air which existsinternally and is involved in their construction, causing a rising andfalling movement, produces friction against the membrane. The way inwhich they move this region is like the motion due to the lungs inanimals that breathe the outer air, or to the gills in fishes. Whatoccurs is comparable to the suffocation of a respiring animal byholding its mouth, for then the lung causes a heaving motion of thiskind. In the case of these animals this internal motion is notsufficient for refrigeration, but in insects it is. It is byfriction against the membrane that they produce the humming sound,as we said, in the way that children do by blowing through the holesof a reed covered by a fine membrane. It is thus that the singingcrickets too produce their song; they possess greater warmth and areindented at the waist, but the songless variety have no fissure there.Animals also which are sanguineous and possess a lung, though thatcontains little blood and is spongy, can in some cases, owing to thelatter fact, live a long time without breathing; for the lung,containing little blood or fluid, can rise a long way: its ownmotion can for a long time produce sufficient refrigeration. But atlast it ceases to suffice, and the animal dies of suffocation if itdoes not respire-as we have already said. For of exhaustion thatkind which is destruction due to lack of refrigeration is calledsuffocation, and whatsoever is thus destroyed is said to besuffocated.We have already stated that among animals insects do not respire,and the fact is open to observation in the case of even smallcreatures like flies and bees, for they can swim about in a fluidfor a long time if it is not too hot or too cold. Yet animals withlittle strength tend to breathe more frequently. These, however, dieof what is called suffocation when the stomach becomes filled andthe heat in the central segment is destroyed. This explains also whythey revive after being among ashes for a time.Again among water-animals those that are bloodless remain alivelonger in air than those that have blood and admit the sea-water,as, for example, fishes. Since it is a small quantity of heat theypossess, the air is for a long time adequate for the purposes ofrefrigeration in such animals as the crustacea and the polyps. It doesnot however suffice, owing to their want of heat, to keep them finallyin life, for most fishes also live though among earth, yet in amotionless state, and are to be found by digging. For all animals thathave no lung at all or have a bloodless one require lessrefrigeration