CHAMELEONS. 7/ 



becomes of a yellow green, till it recovers its 

 liberty, is well nourished, and without pain, 

 when it regains its former colour ; this being the 

 consequence of an equilibrium in the liquids, 

 and of a due proportion of them in the vessels." 



To mention the various hypotheses by which 

 these interesting changes of colour have been at- 

 tempted to be explained, would not suit our 

 pages ; we content ourselves with adding the 

 conclusions of Dr. Milne Edwards, who, in an 

 elaborate memoir on the subject, is considered by 

 some to have solved the problem. We have 

 room only for the results at which he arrives, 

 which he embodies in the following propositions : 



1. That the change in the colour of Chameleons 

 does not depend essentially either on the more or 

 less considerable swelling of their bodies, or the 

 changes which might hence result to the condi- 

 tion of their blood or circulation ; nor does it de- 

 pend on the greater or less distance which may 

 exist between the several cutaneous tubercles, 

 although it is not to be denied that these cir- 

 cumstances probably exercise some influence upon 

 the phenomenon. 



2. That there exists in the skins of these animals 

 two layers of membraneous pigment, placed the 

 one above the other, but disposed in such a way 

 as to appear simultaneously under the cuticle, 

 and sometimes in such a manner that the one 

 may hide the other. 



3. That everything remarkable in the changes 

 of colour that manifest themselves in the Chame- 

 leon, may be explained by the appearance of the 

 pigment of the deeper layer to an extent more or 

 less considerable, in the midst of the pigment of 



