Of the Cameleon.
The cameleon is a native of the torrid zone, and is a genus of the lizard: the faculty of assuming the colour of every object it approaches is ascribed to it, and other singular properties; but there are many rare phoenomena not so well understood, such as its absorption and expulsion of air at pleasure, its property of living a considerable time without any kind of nourishment, and its extraordinary visual advantages, which are perhaps not to be found in any other of the wonderful works of the creation.
I have made various experiments to ascertain these extraordinary properties in this little animal; and I brought home one in a preserved state.
The first object which struck my attention, was the variation of colour; and I am persuaded that it does not assume these from the surrounding objects, but that they proceed from internal sensations of pain, or otherwise.
From the moment that the liberty of my captive was infringed upon, or when interrupted in its pursuits, it became less sensible of external objects, the vivacity of its colour, and the plumpness of its form underwent a visible change. Its natural colour is a beautiful green; and when in a state of liberty it is to be found in the grass, or lodged on the branches of some tree, ornamented with the gayest foilage; and it would appear that its liberty, and the privilege of living in the grass, are indispensible towards the preservation of its qualities. The colour of its skin, in a perfect state of health, is scarcely discernible from the trees and grass, in which it delights to conceal itself, and is not to be discovered at all without a very minute scrutiny. It remains immoveable for a length of time, and its motions are all cautious and slow, continuing to loll out its tongue, which is long and glutinous, in order to secure the little insects that are necessary to its nourishment; and I doubt not but it has an attractive influence over its prey, for I have observed them continually floating around the cameleon, when scarcely discernible in any other space. When the tongue is covered with a sufficient quantity it draws it in instantaneously, and by incessantly repeating the operation, all the insects within its reach are taken in the snare.
That its health and existence depend upon being in the grass, I am persuaded, from the change occasioned by placing it in gravel or sand, when it immediately assumes a yellow tinge, its form is reduced considerably, and the air expelled, with which the body of this animal is inflated, so as visibly to reduce the size. If they are irritated in this situation, they expell the air so strong as even to be heard, gradually decreasing in size, and becoming more dull in colour, until at length they are almost black; but upon being carried into the grass, or placed on the branches of a tree, they quickly assume their wonted solidity and appearance.
The victims of my observation I have frequently wrapped in cloth of various colours, and have left them for a considerable time, but when I visited them I did not find that they partook of any of the colours, but uniformly were of a tarnished yellow, or greyish black, the colours they always assume when in a state of suffering and distress, and I never could succeed in making them take any other when in a situation of constraint. The skin of the cameleon is of a very soft and delicate texture, and appears to the observer similar to a shagreen skin, elastic and pliable; and it may be owing to this extraordinary construction that it changes its colours and size with that facility which astonishes us; but what may be considered as a more wonderful faculty is, its expanding and contracting itself at pleasure, and, as it were, retaining the fluid in an uniform manner, when in health, but exhaling it when in a state of suffering, so as to reduce its dimensions to a more contracted size. Its peculiar organization is such, that the atmospheric air which it inhales so generally throughout every part of its body, distends and projects even its eyes and extremities. I have frequently seen it after many days fasting become suddenly plump, and continue so for a fortnight, when immediately it became nothing but a skeleton of skin and bone.
The tenuity of its body is at these seasons astonishing, the spine of its back becomes pointed, the flesh of its sides adhere to each other, and apparently form one united subsance, when it will, in a few hours, at pleasure, resume its rotund state; and this appears to me to be a most extraordinary circumstance in the construction of this animal, which invites the minutest research of the naturalist.
To convince myself how far the assertion might be admitted, that the cameleon can exist upon air, I have placed them in a cage, so constructed, as to exclude any thing else, even the minutest insect; when I have visited my captives, they have opened their mouths and expelled the air towards me so as to be felt and heard. In the first stage of their privation and imprisonment, which has continued for more than a month, I have found them in continual motion around their prison, but afterwards their excursions became more circumscribed, and they have sunk to the bottom, when their powers of distension and contraction became languid and decreased, and were never again capable of performing their accustomed transformation. The one which I brought to England preserved in spirits, after undergoing upwards of two months of famine, when I carried it among the grass, or placed it in the thick foliage of a tree, in little more than a week regained its green colour, and power of expansion; but not contented with my experiment, and determined to ascertain it to the utmost, I redoubled my precautions to exclude every thing but air, and my devoted victim was doomed to another series of trial, and continued to exist upwards of a month, when it fell a sacrifice to my curiosity.
The eyes of the cameleon may also be considered a remarkable singularity; they are covered with a thin membrane, which nature has given it to supply the want of eye-lids, and this membrane is sunk in the centre by a lengthened hole, which forms an orifice, bordered by a shining circle. This covering follows all the motions of the eye so perfectly, that they appear to be one and the same; and the aperture, or lengthened hole, is always central to the pupil, the eyes moving in every direction, independant of each other; one eye will be in motion while the other is fixed, one looking behind while the other is looking before, and another directed above while its companion is fixed on the earth, so that its eyes move in every possible direction, independant of each other, without moving the head, which is closely compacted with the shoulders.