which are destitute of red blood. Of these, he says there are several genera: the mollusca, such as the cuttlefish, which is externally soft with an internal firm part; the crustacea, internally soft and covered with a firm integument, such as the crab; the testacea, internally soft and externally hard and solid, as the limpet and oyster. The insects form the fourth genus; and are distinguished by their being externally and internally formed of a hardish or cartilaginous substance, and divided into segments; some of them having wings, as the wasp; while others have none, as the centipede. He then gives a pretty full account of the cuttlefish and nautilus, treats of the crustaceous animals generally, and enters into details respecting the other two classes. After this he enumerates the organs of sensation, stating that man, and all the red-blooded and viviparous animals, possess five senses, although in the mole vision is deficient. He describes correctly the eye of that creature, showing that it is covered by a thickish skin, but presents a conformation similar to that of other animals, and is furnished with a nerve from the brain. He shows that although fishes have no visible organs of smelling or hearing, they yet possess both senses, and, in treating of this subject, states many interesting facts relative to the mode employed in catching dolphins. He also shows that insects have the faculty of hearing and smelling. The testacea, he says, besides feeling, which is common to all animals, have smell and taste; but he also asserts that some of them, the solen and pecten, are capable of seeing, and others of hearing.

All viviparous quadrupeds not only sleep, but also dream; but whether the oviparous dream is uncer

tain; although it is plain that they sleep, as do the aquatic animals, fishes, mollusca, testacea, and crustacea. A transition is then made to the subject of sex, for the purpose of showing that in the mollusca, crustacea, testacea, and eels, there is no difference in that respect between individuals of the same species.

The subjects of generation and parturition occupy the fifth, sixth, and seventh books. From the comparatively large space which he has devoted to the result of his inquiries in these departments, the minuteness with which he describes the phenomena presented by them in man and the domestic animals, and the accurate knowledge which he frequently exhibits, it may be inferred that they were favourite subjects with Aristotle. It is sufficient for our purpose to mention some of the cases in which he attained the truth, and others in which he failed.

He describes the membranes with which some of the mollusca envelope their eggs, mentions the changes through which insects pass before they acquire the perfect state, and speaks with tolerable accuracy of the economy of bees and wasps. He states, however, that the former make wax from flowers, but gather their honey from a substance which falls from the air upon trees. The eggs of tortoises, he says, are hard, like those of birds, and are deposited in the ground. His remarks on those of lizards and the crocodile are also correct. He states accurately that some serpents bring forth their young enclosed in a soft membrane, which they afterwards burst; but that sometimes the little animals escape from the egg internally, and are produced free. Other serpents, he observes, bring forth eggs cohering in the

form of a necklace. On the eggs of birds his observations are nearly as correct as those which we find in books at the present day. He was acquainted with their general structure, and the development of the chick, which he minutely describes. He remarks of the cuckoo, that it is not a changed hawk, as some have asserted; that, although certain persons have alleged that its young have never been seen, it yet certainly has young; that, however, it does not construct a nest, but deposites its eggs in the nest of other birds, after eating those which it finds there.

He remarks that the cartilaginous fishes are viviparous, but that the other species bring forth eggs, and states correctly that they have no alantoid membrane. He then passes to the cetacea, with which he seems to be nearly as well acquainted as modern naturalists, and reverts to the oviparous fishes, respecting which he presents numerous details. He maintains, however, that the eel is produced spontaneously, and that no person had ever detected eggs or milt in it.

Having discussed the subject of generation, he proceeds, in the eighth book, to treat of the food. and actions of animals, their migrations, and other circumstances. The ninth consists of a multitude of topics without any direct relation to each other, but apparently treated as they had successively presented themselves to the author. Thus, at the commencement we find remarks on the peculiarities of disposition observed in the males and females of different animals, the combats of hostile species, the actions of animals, nidification, generation, and other matters.

Several species of different classes

are then described, such as the kingfisher, the blackbird, the cuckoo, the marten, eagles, owls, fishes, insects, and quadrupeds.

The fragments which remain of Aristotle's History of Animals may, perhaps, be considered as presenting the general views which he had intended to precede his more particular descriptions; but, regarded even in this light, it cannot be denied that they are extremely deficient in method. There is in them no approach to a regular classification, we do not say of animals, but of subjects to be discussed. He is continually making abrupt transitions, seems to lose sight of the object more immediately in view, to indulge in digressions foreign to it, and frequently repeats a circumstance which he had related before. His work resembles the rude notes which an author makes previous to the final arrangement of his book; and such it may possibly have been. Of descriptions, properly so called, there are few, those of the elephant, the camel, the bonasus, the crocodile, the chameleon, the cuckoo, the cuttlefish, and a few others, being all that we find.

It may appear strange, that the statements of naturalists should so frequently prove incorrect. In how many works, even of the present day, are errors to be discovered, which might have been avoided by a proper use of the organs of vision, and a resolution to take nothing on trust! But it is much easier to employ the imperfect remarks of others, to collect from books, compare and arrange, than to seek or make opportunities of observation for one's self; and of so little consequence do some men hold the actual inspection of natural objects, that,

without practising it to any extent, they nevertheless arrogate to themselves the title of philosophical inquirers.

In fine, the observations of Aristotle, considering the period at which he lived, and the proneness of the human intellect to wander from the true path, are remarkable for the great proportion of truth which they present to us. Whatever may be their actual merits, they are certainly superior to those of any other naturalist whose works have come down to us from the remote ages of classical antiquity; and we may take leave of this distinguished man by observing, in the words of Dr Barclay, that, "notwithstanding his many imperfections, he did much both for anatomy and natural history, and more, perhaps, than any other of the human species, excepting such as a Haller or Linnæus, could have accomplished in similar circumstances."

The best edition of his History of Animals (IIεg Zwwv 'Isogia), is that of Schneider, in 4 vols 8vo, which issued from the press at Leipsic in 1811. Many editions of his works have been published; but the most complete is said to be Sylburge's, printed at Frankfort, containing,-Organon, 1585; Rhetorica et Poetica, 1584; Ethica ad Nicomachum, 1584; Ethica Magna, &c. 1584; Politica et Economica, 1587; Animalium Historia, 1587; De Animalium Partibus, &c. 1585; Physicæ Auscultationis, lib. viii. et Alia Opera, 1596; De Cœlo, lib. iv.; De Generatione et Conceptione; De Meteoris, lib. iv.; De Mundo; De Anima; Parva Naturalia; Varia Opuscula, 1587; Alexandri et Cassii Problemata, 1585; Aristotelis et Theophrasti Metaphysica, 1585.