the chameleon brings both of its eyes to bear upon the object. "Notwithstanding," says Weissenbaum, "the strictly symmetrical construction of the chameleon as to its two halves, the eyes move independently of each other, and convey different impressions to the different centres of perception: the consequence is that, when the animal is agitated, its movements appear like those of two animals glued together. Each half wishes to move its own way, and there is no concert of action. The chameleon, therefore, is not able to swim like other animals; it is so frightened when put into water that the faculty of concentration is lost, and it tumbles about as if in a state of intoxication. Nay, more, the chameleon may be asleep on one side and awake on the other."
The chameleon is often seen to inhale air, gulp after gulp, with great avidity, thus inflating its body enormously, even to the feet and tail. As has been already stated, the animal's lungs are very large—so large, indeed, that it was supposed by Pliny (who simply transcribes the accounts given by Greek authors) that the lungs almost filled the entire cavity of the body; these lungs connect with the air-cells beneath the skin. By taking air into the lungs, whence it passes into the air-cells, the chameleon is able to inflate itself to as much as twice its ordinary size; and often it remains so inflated for a long time, now slightly collapsing, again swelling out, till the skin becomes as tense as the head of a drum. No doubt it was this power of self-inflation which led the ancients to suppose that, "alone among animals, the chameleon neither eats nor drinks, its only sustenance being air."—(Pliny.)
But the color-changes of the chameleon form perhaps the most interesting phenomenon connected with this animal. We need not repeat the fabulous stories told about these color-changes: the facts which can be strictly verified by direct observation are wonderful enough without the adornments of imagination. These changes of color range from whity-yellow, through yellow, bright and dark green, to dull black; and these diversities of coloration may affect the entire surface of the animal, or one or other of its sides, or may appear only in spots. When the chameleon is asleep, and not exposed to the direct rays of the sun, its color is a whity-yellow; when basking in the sun, it is a dingy black or dusky brown. On being aroused from sleep, the side which is first awakened assumes a darker shade. There is reason for believing that sunlight, apart from the warmth which accompanies it, is very grateful to the chameleon, and, in response to this stimulus, he at once begins his play of color. M. Paul Bert, a French savant, whose name is familiar to the readers of The Popular Science Monthly, has for some time been engaged in studying the anatomy and mechanism of these phenomena. His researches are not yet completed, but we may state some of the facts which he has established.
