112 



LEAVES FROM THE NOTE-BOOK OF A NATURALIST. 



half a finger's breadth, reaching from the crest of ] passions of the creature. He holds that, when a 



the spine to the middle of the back ; and others 

 appeared on the ribs, forelegs, and tail. All the 

 spots were of an Isabella color, through the mix- 

 ture of a pale yellow, with which the granules 

 were tinged, and of a bright red, which was the 

 color of the skin that was visible between the 

 granules ; the rest of the skin not in the sun's 

 light, and which was of a paler gray than ordina- 

 ry, resembled a cloth made of mixed wool, some of 

 the granules being greenish, others of a tawny 

 gray, and others of the usual bluish gray, the 

 ground remaining as before. When the sun 

 ceased to shine, the original gray appeared again 

 by degrees, and spread itself all over the body, 

 except under the feet, which continued nearly of 

 the same color, but rather browner. When, in 

 this state of color, it was handled by strangers, 

 several blackish spots about the size of a finger- 

 nail appeared a change which did not take place 

 when it was handled by those who usually took 

 care of it. Sometimes it was marked with brown 

 spots which inclined towards green. It was 

 wrapped in a linen cloth, and, after two or three 

 minutes, was taken out whitish, but not so white 

 as that which the vir nobilifsimus above alluded to 

 subjected to a similar experiment. Theirs, which 

 had only changed its ordinary gray into a paler 

 gray, after having retained that color some time, 

 lost it gradually. This experiment made them 

 question the truth of the allegation that the cha- 

 meleon takes all colors but white, as Theophras- 

 tus and Plutarch report ; for theirs seemed to 

 have such a disposition to retain this color that it 

 grew pale every night, and when dead it showed 

 more white than any other color. Nor did they 

 find that it changed color all over the body, as 

 Aristotle reports ; for, according to their experi- 

 ence, when the animal takes other colors than 

 gray, and disguises itself to appear in masquerade, 

 as ^Elian pleasantly observes, it covers only cer- 

 tain parts of the body with them. They, finally, 

 laid their chameleon on substances of various 

 colors, and wrapped it up in them ; but it did not 

 take those colors as it had taken the white, and, 

 indeed, they allow that it only took the white the 

 first time the experiment was made, though it was 

 repeated several times and on different days. 



Hasselquist's experiments with regard to the 

 mutability of color were followed by nearly the 

 same consequences as mine ; but he thought that 

 the changes depended on a sort of disease, a kind 

 of jaundice, to which the animal was subject, 

 particularly when it was irritated. 



The blood, in the opinion of M. d'Obsonville, 

 was the cause of the change. That fluid, accord- 

 ing to him, is, in the chameleon, of a violet blue, 

 which color, he says, it will retain on linen or 

 paper for some minutes, if it be previously steeped 

 in a solution of a^m. The coats of the blood- 

 vessels he found to be yellow, both in their main 

 trunks and ramifications, and he comes to the 

 conclusion that green will be the product. Like 

 Hasselquist, he attributes the change of color to the 



lealthy chameleon is provoked, the circulation is 



accelerated, the vessels spread over the skin dis- 



ended, and so a superficial blue-green color is 



>roduced ; but when the animal is shut up, deprived 



if free air and impoverished, the circulation be- 



omes sluggish, the vessels are not well filled, and 



he languid chameleon changes to a yellow-green, 



which continues during its imprisonment. 



Others, the late Sir John Barrow for instance, 

 have observed that, previous to a change, the 

 chameleon makes a long inspiration, when the 

 >ody is inflated so as to appear twice its usual 

 size, and, as the inflation subsides, the change of 

 color is gradually manifested, the only permanent 

 marks being two small dark lines along the sides ; 

 and it has been argued, from this description, that 

 he reptile owes its varied tints to the influence of 

 oxygen. Mr. Houston is also of opinion that the 

 ihange depends on the state of turgescency of the 

 skin ; and Mr. Spittal regards it as connected with 

 respiration and the state of the lungs. Theories 

 upon theories, as varied as the tints which they 

 profess to explain, have been broached to account 

 "or these changes ; but, without dwelling longer 

 upon them, let us turn to the solution of M. Milne 

 Edwards, who, in an elaborate paper published in 

 the Annales des Sciences Naturelles for January, 

 1834, came to the conclusion that the color of 

 chameleons does not depend essentially on the 

 greater or less inflation or expansion of their 

 jodies, or the changes which might thence take 

 >lace in the circulation or condition of the blood ; 

 nor on the distance between the several tubercles 

 or granules of the skin ; but, at the same time, he 

 does not deny that those circumstances may prob- 

 ably exercise some influence. He shows that 

 there exist in the skin of these reptiles two layers 

 of membranous pigment, one above the other, but 

 so disposed as to appear simultaneously under the 

 cutici<;, and sometimes in such a manner that the 

 one may be hidden by the other ; and he insists 

 that everything remarkable in the changes of the 

 chameleon's color may be explained by the ap- 

 pearance of the pigment of the lower layer to an 

 extent more or less considerable in the midst of 

 the pigment of the upper layer, or by its disap- 

 pearance beneath that layer. That these displace- 

 ments of the lower pigment do actually occur he 

 proves, and he derives from those facts the proba- 

 ble consequence that the chameleon's color changes, 

 not only during life, but that it may vary after 

 death. He also observes, that there is a close 

 analogy between the mechanism which causes the 

 changes of color in these lacertians and that which 

 governs the appearance and disappearance of col- 

 ored spots in the mantles of several of the cephal- 

 opods or cuttles. 



So long ago as July, 1819, Signer Giosu 

 Sangiovanni read to the Royal Academy of Sci- 

 ences at Naples his able and interesting paper, 

 intituled Descrizione di un particolare Sistema di 

 Organi, e de* Fenomeni cA' esso produce ; scoverto 

 ne 1 Molluschi Cefalopodi, in which he described the 



