818 Mr Edwards on Change of Colour in the Chameleon. 



and was only to be found under the greyish pigment, by which 

 it was now again completely covered over. 



When to the skin of the animal which had just died, I ap- 

 pHed some concentrated alcohol, the dark purple colour almost 

 immediately disappeared, and in its place was to be seen that 

 tint, which, during the life of the chameleon, unusually pervades 

 it during profound sleep. The greater part of the stronger 

 acids produced the same effect ; but when I applied a solution 

 of alkali to a part of the skin which presented the natural yel- 

 lowish-grey colour of the superficial pigment, the exactly oppo- 

 site change was effected, the colour immediately changed to a 

 dark red. 



Finally, in small shreds of the skin which I detached from 

 the body, I could make the colour change from the yellowish- 

 grey to the violet-red by mechanical means alone, viz. by press- 

 ing the deeper pigment towards the surface of the skin ; and 

 when, after this, I examined these portions with the microscope, 

 I found them of the same appearance with those similar tints 

 resulting from the physiological actions respecting which it was 

 my object to discover the nature. 



The results being the same, it might be presumed that the 

 causes were analogous, and it would then follow, that during 

 life, the deeper pigment, according as it was hidden in the sub- 

 stance of the skin, or shewed itself in a greater or less degree in 

 the midst of the more superficial pigment, occasioned the phe- 

 nomena of coloration or of decoloration of which we have al- 

 ready described all the appearances. But another inquiry yet 

 remains, viz. How this inferior pigment could now protrude in- 

 to, and now retire from, the more superficial one ? For the so- 

 lution of this question I again had recourse to an examination of 

 the structure of the skin. 



Having digested for some time a portion of the skin in a 

 strong solution of alkali, for the purpose of dissolving or mak- 

 ing transparent the parts which concealed the position of the pig- 

 ment, I then dissected it under a strong magnifying glass, and I 

 distinctly perceived that the dark colouring matter was contain- 

 ed in a great number of small cavities which were situated in 

 the substance of the skin, from each of which originated very mi- 

 nute ramifications which extended to the scarf-skin, so traversing 



