Quadrupeds, Serpents, Birds, Fishes, Cetacea.
White-blooded Animals.
Testacea, Crustacea, Mollusca, Insects.
It must, however, be understood, that Aristotle proposes no formal distribution of animals, and that his ideas respecting families, groups, or genera, such as those of our present naturalists, are extremely vague.
His quadrupeds include the mammalia and the quadrupedal reptiles. He divides them into those which are viviparous, and those which are oviparous; the former covered with hair, the latter with scales. Serpents are also scaly, and, excepting the viper, oviparous. Yet all viviparous animals are not hairy; for some fishes, he remarks, likewise bring forth their young alive. In the great family of viviparous quadrupeds also, he says, there are many species (or genera), as man, the lion, the stag, and the dog. He then mentions, as an example of a natural genus, those which have a mane, as the horse, the ass, the mule, and the wild-ass of Syria, which are severally distinct species, but together constitute a genus or family.
This introduction to the History of Animals the philosopher seems to have intended, less as a summary of his general views respecting their organization and habits, than as a popular exordium, calculated to engage the attention of the reader, and excite him to the study of nature. Whatever errors it may contain, and however much it may be deficient in strictly methodical arrangement, it is yet obviously the result of extensive, and frequently accurate observation. He then proceeds to the description of the different parts of the human body, first treating of what anatomists call the great regions, and the exterior generally, and then passing to the internal organization. His descriptions in general are vague, and often incorrect. As an example, we may translate the passage that refers to the ear.
This organ, he says, is that part of the head by which we hear; but we do not respire by it, for Alcmeon's opinion, that goats respire by the ears, is incorrect. One part of it has no name, the other is called lobos; it consists entirely of cartilage and flesh. The internal region is like a spiral shell, resembling an auricle at the extremity of the bone, into which as into a vessel the sound passes. Nor is there any passage from it to the brain, but to the palate; and a vein stretches from the brain to it. But the eyes belong to the brain, and each is placed upon a small vein. Every animal that has ears moves them, excepting man; for of those which are furnished with the sense of hearing, some have ears, others none, but an open passage; of which kind are feathered animals, and all that are covered with a scaly skin. But those which are viviparous, the seal, the dolphin, and other cetacea excepted, have external ears, as well as the viviparous cartilaginous animals. The seal has a manifest passage for hearing; but the dolphin, although it hears, yet has no ears. The ears are situated at the same level as the eyes, but not higher, as in certain quadrupeds. The ears of some persons are smooth, of others rough, or partly so; but this furnishes no indication of disposition. They are also large, small, or of moderate size, projecting, or flat, or intermediate. The latter circumstance indicates the best disposition. Large and projecting ears are indicative of a fool and babbler.
From this passage we perceive that Aristotle was acquainted with the Eustachian tube; although his anatomical knowledge of the ear is certainly of the most superficial kind, and his physiognomical notions respecting it sufficiently ludicrous. He divides the body into head, neck, trunk, arms, and legs, much as we do at the present day. The head consists of the calvaria, or part covered with hair, which is divided into three regions, the bregma or fore part, the crown, and the occiput. Under the bregma is the brain; but the back part of the head is empty. When speaking of the face, he remarks, that persons having a large forehead are of slow intellect, that smallness of that part indicates fickleness, great breadth stupidity, and roundness irascibility. The physiognomists of our day have a different opinion. The neck contains the spine, the gullet, and the arteria (or windpipe). The trunk consists of the breast, the belly, &c.;—and in this manner he passes over the different external regions.
In describing the brain, he states that all red-blooded animals have that organ, as have also the mollusca, and that in man it is largest and most humid. He had observed its two membranes, as well as the hemispheres and cerebellum; but he asserts that it is bloodless, that no veins exist in it, and that it is naturally cold to the touch. He was ignorant of the distribution of the nerves, was not aware that the arteries contain blood, imagined that the heart being connected with the windpipe is inflated through it, and, in a word, manifests extreme ignorance of every thing that relates to the internal organization.
Judging from this specimen, the reader may suspect that his time would not be profitably employed in separating the few particles of wheat from the great mass of chaff which the writings of Aristotle present to us. Nor must it be concealed that the modern naturalist does not consult his volumes for information, but merely to gratify curiosity. There is to be found, indeed, in the most imperfect of our elementary works on anatomy, whether human or comparative, more knowledge than was probably contained in the Alexandrian library.