814 Mr Edwards on Change of Colour in the Chameleon, 



researches, and consequently we nowhere find the guarantee of 

 strict accuracy. 



According to Hasselquist, these changes of colour depend on 

 a kind of disease; more expressly, a kind of jaundice to wliich 

 the animal is unfortunately subject ;< and especially when it is 

 put in a rage. ,.< • ; ' ' .. ''^ ?'" 



Another author has more lately explained the phenomenon, by 

 stating that the blood of the chameleon is of a violet blue colour, 

 whilst the coats of the bloodvessels, and of the skin itself, are 

 yellow, so that the colour of the skin changes accordingly as it 

 is abundantly supplied with blood, or the reverse. 



Cuvier regards the changes of colour as probably owing to 

 the immense size of the reptile's lungs ; and that according as 

 these organs are full or are empty of air, they make the whole 

 body more or less transparent, by forcing a larger or smaller 

 quantity of blood into the integuments, and even colouring this 

 fluid itself with hues more or less brilliant. 



There are other naturalists, who, whilst they attribute these 

 changes to the respiration, explain the effect of the pulmonary 

 distentionon the skin in a different way. The common integu- 

 ments of the chameleon, as is generally known, is furnished with 

 a great number of small scaly granules which make it to re- 

 semble shagreen : it is said then, that these granules are of a 

 yellowish colour, whilst the deeper portion is of a dark red 

 tint, and if this membrane is much contracted, the granula- 

 tions alone are seen ; whilst, on the other hand, if the skin 

 be disturbed by the enlargement of the lungs, these same gra- 

 nules separate the one from the other, and thus exhibit the na- 

 tural colour of the skin, from which results all the various 

 hues which are ever presented. 



'Mr Spittal, to whom we are indebted for some interesting 

 observations on these changes, regards them as connected with 

 the state of the lungs ; and Mr Houston, who has enriched 

 science by his researches upon the structure and motions of the 

 tongue in these strange animals, considers this phenomenon as 

 dependent on the vascular turgescency of the skin. 



Finally, it might moreover to be inquired, whether these va- 

 riations in colour were not owing to some peculiar construction of 

 the scarf-skin, which, by itself changing, might act on the light 



