But for these shades of colour, or for any other, we should look in vain in the animal of the Tower Menagerie, which, in consequence of a particular conformation, not unfrequent in some species of animals, and occasionally met with even in the human race, is perfectly and purely white. In order to explain this phenomenon, which is one of the most curious, but at the same time one of the most simple in physiology, it is necessary to observe that there exists beneath the epidermis, or outer covering of the skin, both in man and animals, a peculiar membrane of very fine and delicate texture, which is scarcely visible in the European but sufficiently obvious in the Negro, termed by anatomists the rete mucosum. In this net-work is secreted, from the extremities of the minute vessels which terminate upon its surface, a mucous substance which varies in colour according to the complexion of the individual, of the varieties in which it is the immediate cause; and from the substance thus secreted the colouring matter of the hairs and of the iris is derived. The pure whiteness then of the covering of the animal in question, and of all those which exhibit a similar variation from their natural tinge, is attributable solely to the absence of this secretion from whatever cause. It is always accompanied, as in the present instance, by a redness of the eyes, arising from the blood-vessels of the iris being exposed to view in consequence of the want of the usual coating formed by this secretion, by which they are naturally protected from the too great influence of the light. In the human race the individuals who are thus afflicted, characterized by the dull whiteness of their skins, the deep redness of their eyes, and their colourless, or, as it is generally termed, flaxen, hair, are called Albinos. They are generally timid in disposition, languid in character, and weak both in mind and body. The same original conformation, for it is always born with the individual and never acquired in after life, although sometimes prolonged beyond its limits in the shape of an hereditary legacy, is common to many animals. Perhaps the most familiar instances among these are the white mice, the white rabbits, and the white pigeons, which are known to every one. But it has also been occasionally seen in many other species, as monkeys, squirrels, moles, pigs, and even cows and horses, and, to come a little closer to our present subject, in goats and deer. Not even that massive and stupendous beast the Elephant is exempted from its influence. It can hardly be necessary to recall to the reader the title on which the ruler of millions of not uncivilized Asiatics, the Burmese monarch, prides himself more than on any other, inasmuch as it is the emblem of power and prosperity, that of Lord of the White Elephant; a title, which, while it demonstrates the fact of the existence of this deviation in the Elephant as well as in other animals, proves also the extreme rarity of its occurrence. It has moreover been noticed in many species of birds.
THE JAVANESE CIVET.
All these birds were comprehended by Linn?us under the generic name of Strix, but later naturalists have subdivided them into several genera, dependent on the size of the ears and of the ocular discs, on the presence or absence of two remarkable tufts of feathers on the head having somewhat the appearance of horns, and on the covering of the legs and feet. The Virginian Horned Owl is spread over nearly the whole continent of America from north to south. Its plumage is brown above, marked with numerous transverse black stripes, and the feathers of the under surface are of a dirty white, transversely striped with blackish-brown.
THE BONNETED MONKEY.
The Asiatic Elephant was until very lately considered as forming one species with the African, the clear and obvious distinctions which exist between them never having been noticed until pointed out by M. Cuvier, notwithstanding that both have been familiarly known for more than two thousand years to the nations of Europe, the former having formed an important part of the armament with which Porus withstood the conquering arms of Alexander, and having been subsequently introduced even into Italy by Pyrrhus; and the latter, as we may fairly presume, furnishing those individuals which were employed in the warlike array of the Carthaginians. The Asiatic animal appears when fully grown to attain a larger size than the African, the females commonly measuring from seven to eight, and the males from eight to ten feet in height, and sometimes weighing six or seven thousand pounds. His head is more oblong, and his forehead presents in the centre a deep concavity between two lateral and rounded elevations; that of the African being round and convex in all its parts. The teeth of the former are composed of transverse vertical lamin? of equal breadth, while those of the latter form rhomboidal or lozenge-shaped divisions. The ears of the Asiatic are also smaller and descend no lower than his neck, and he exhibits four distinct toes on his hind feet: the African on the contrary is furnished with ears of much greater size, descending to his legs, and no more than three toes are visible on his posterior extremities. These differences are so striking and important, and indeed, so far as regards the form of the head and the structure of the teeth, so essential, that it is impossible not to adopt the division which has been founded upon them, and to consider the natives of the two continents as originally and specifically distinct.