Page:Natural History, Reptiles.djvu/84

76 in open air, and well fed, it becomes a blue green, but when feeble, or deprived of free air, the prevailing tint is yellow green. Under other circumstances, and especially at the approach of one of its own species, no matter of which sex, or when surrounded and teased by a number of insects thrown upon him, he then almost in a moment takes alternately the three different tints of green. If he be dying, particularly of hunger, the yellow is at first predominant; but in the first stage of putrefaction this changes to the colour of dead leaves.

“The causes of these changes are various; and first, the blood of the Chameleon is of a violet blue, which colour it will preserve for some minutes on linen or paper, especially on such as have been steeped in alum-water. In the second place, the different tunicles of the vessels are yellow, as well in their trunks as in their ramifications. The epidermis, or exterior skin, when separated, is transparent, without any colour; and the second skin is yellow, as are all the little vessels that touch it. Hence it is probable that the change of colour depends upon the mixtures of blue and yellow, from which result different shades of green. Thus, when the animal, healthy and well-fed, is provoked, its blood is carried in greater abundance from the heart towards the extremities; and swelling the vessels that are spread over the skin, its blue colour subsides, and with the yellow of the vessels, produces a blue green, that is seen through the epidermis. When, on the contrary, the animal is impoverished, and deprived of free air, the exterior vessels being more empty, their colour prevails, and the animal