animals were in health, a change generally took place 

 in the shade every ten minutes; but at night little 

 alteration was perceptible, and the hue was more 

 permanent. Mr. Spittal observes, that he feels as- 

 sured, he " observed the shadow of the wires of the 

 cage, during the bright sunshine, through the body 

 of one of them while in a compressed state, and we 

 are told that the chameleon, in a wild state, often 

 appears as if it were translucent or semi-transparent. 



Mr. Madden informs us, that the chameleon is so 

 exceedingly irascible, that he easily trained two large 

 ones to fight, which they would do on causing them to 

 strike their tails the one against the other. During 

 their excitement, the change of colour becomes very 

 conspicuous, though, by Mr. A. Scott's communication 

 to us, the animal may be irritated without this mu- 

 tation of colour supervening. Mr. Madden supposes 

 that the bile of the chameleon, being visible in the 

 blood under the pellucid skin, affords, as it passes 

 through the circulation, three distinct shades of green. 

 This seems, however, to be the introduction of an 

 occult cause, nor is it necessary to suppose any other 

 than an accelerated circulation to account for the 

 phenomenon. A languid or hurried circulation will 

 necessarily be connected with a greater or lesser 

 degree of oxygenation, a fact proved by the variable 

 temperature exhibited in the colours of the skin : 

 venous blood is dark, and arterial a bright red colour ; 

 and these colours depend on chemical change ; they 

 are of different temperatures, and intermediate shades 

 may be formed by their mixture. 



Monconis relates, that the chameleon appears green 

 in 'the sunbeam, and black when seen by candle-light. 

 Perhaps Merrick, on this assumption, has ventured to 

 record the circumstance. That it can change to a deep 



