76 SAURIA. — CHAM^LEONID^. 



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 

 w^hen 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 d}ing, 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 ramifi- 

 cations. 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 



