The first book contains a brief description of the parts of which the bodies of animals are composed. The introduction consists of general propositions; of which we shall present a few of the more remarkable as a specimen.
Some parts, he observes, are simple, and divided into similar particles; while others are compound, and consist of dissimilar elements. The same parts in different animals vary in form, proportion, and other qualities; and there are many creatures which, although they have the same parts, have them in different situations. Animals differ in their mode of living, actions, and manners: thus, some reside on land, others in water; and of the latter some breathe water, others air, and some neither. Of aquatic animals, some inhabit the sea, others the rivers, lakes, or marshes. Of those which live in the sea, some are pelagic, others littoral, and others inhabit rocks. Of land-animals, some respire air, as man; others, although they live on the land and obtain their food there, do not breathe air, as wasps, bees, and other insects.
We know no animal, says he, that flies only, as the fish swims; for those which have membranous wings walk also; and bats have feet, as have seals, although imperfect. But some birds have the feet weak; in which case the defect is compensated by the superior action of the wings, as in swallows. There are many species which both walk and swim. Animals also differ in their habits; thus, some are gregarious, others solitary,—a distinction applicable to them whether they walk, fly, or swim. Some obey a leader, others act independently; cranes and bees are of the former, ants of the latter kind. Some feed on flesh, others on fruits, while others feed indiscriminately; some have homes, others use no covering of this kind, but reside in the open air. Some burrow, as lizards and snakes; others, as the horse and the dog, live above ground. Some animals seek their food at night, others by day; some are tame, others wild; some utter sounds, others are mute, and some sing; all of them, however, sing or cry in some way at the season of pairing.
In this way he proceeds, stating briefly the various circumstances in which animals differ from each other, and in conclusion asserting that man is the only one capable of design; for, says he, although many of them have memory and docility, none but man have the faculty of reflection.
These general propositions or aphorisms are not so simple or so easily attained as one might imagine on reading them inattentively. Let any person who has a tolerably comprehensive idea of the series of animated beings reflect a little, and he will perceive, that such as the following must be derived from the observation of a great number of facts:—Those parts which seize the food, and into which it is received, are found in all animals. The sense of touch is the only one common to all. Every living creature has a humour, blood or sanies, the loss of which produces death. Every species that has wings has also feet.
In this chapter Aristotle divides animals into such as have blood, and such as have it not. Of the former (the red-blooded) some want feet, others have two of these organs, and others four. Of the latter (the white-blooded) many have more than four feet. Of the swimming-animals, which are destitute of feet, some have fins, which are two or four; others none. Of the cartilaginous class, those which are flat have no fins, as the skate. Some of them have feet, as the mollusca. Those which have a hard leathery covering swim with their tail. Again, some animals are viviparous, others produce eggs, some worms. Man, the horse, the seal, and other land-animals, bring forth their young alive; as do the cetacea and sharks. Those which have blow-holes have no gills, as the dolphin and whale. In this department, the observations of the great philosopher are often minute, and generally accurate, although usually too aphoristic and unconnected to be of much use to the student.
Of flying-animals, some, as the eagle and hawk, have wings; others, in place of wings, have membranes, as the bee and the beetle; others a leathery expansion, as the bat. Those which have feathered or leathery wings are blooded (red-blooded); but those which have membranous wings, as insects, are bloodless (white-blooded). Those which fly with wings or with leathery expansions, either have two feet or none; for, says he, it is reported that there are serpents of this kind in Ethiopia. Of the flying bloodless animals, some have their wings covered by a sheath, as beetles; others have no covering, and of these some have two, others four wings. Those which are of large size, or bear a sting behind, have four; but the smaller and stingless, two only. Those which have sheaths to their wings, have no sting; but those which have two wings are furnished with a sting in their fore part, as the gnat.
Animals are distinguished from each other, so as to form kinds or families. These, according to our author, are quadrupeds, birds, fishes, cetacea, all which he says have (red) blood. There is another kind, covered with a shell, such as the oyster; and another, protected by a softer shell, such as the crab. Another kind is that of the mollusca, such as the cuttlefish; and lastly, the family of insects. All these are destitute of (red) blood.
Here, then, we have a general classification of animals, which it is important to notice, as we may have occasion afterwards to compare it with arrangements proposed by other naturalists. It may be reduced to the following form:—
Red-blooded Animals.