532 Observations on the Chameleon. 



Art. III. — On the peculiar Insulation of the Nervous Currents in 

 the Chameleon ; with some Observations on Change of Colour in 

 that Creature. By W. Weissenborn, D. Ph. 



Among the manifold conditions connected with the change 

 of colour in the chameleon, and which I had ample opportu- 

 nities of observing for nine months in the years 1834-5, dur- 

 ing which time I had a living specimen in my possession, 

 there was none which struck me more forcibly as being cu- 

 rious than that one lateral half of the animal is often of a co- 

 lour decidedly different from that of the other. In an article 

 on the habits, colours, tongue, &c, of the chameleon, which 

 I published in M. von Froriep's ' Notizen aus dem Gebiete 

 der Natur- und Heilkunde/ Nos. 965 and 966, June, 1835, I 

 stated that this peculiarity ought to be ascribed to a particu- 

 lar organization, in consequence of which the involuntary 

 nervous currents can be excited in one half of the animal's 

 body, independently of those in the other. I now feel 

 prompted to lay a somewhat greater stress on this point, to 

 establish it more fully, and to call the attention of the read- 

 ers of this Journal to it, as I believe that no animal is better 

 adapted for being made instrumental in promoting the solu- 

 tion of an important problem lately proposed by M. Matteucci, 

 as to the mode of operation of the galvanic currents in the 

 frog and other animals. In the state to which the question 

 has latterly been advanced, almost exclusively, by the inge- 

 nious researches of that philosopher, who, after inventing an 

 apparatus by means of which he obtained sparks from the 

 Torpedo, has lately deduced the most interesting laws from 

 the mode in which the nervous currents of the frog affect the 

 galvanometer, the ultimate solution of the problem rests now 

 chiefly on our overcoming two serious difficulties. — On the 

 one hand, the electrical currents in animals must, of course, 

 describe a full circuit. We therefore want to point out two 

 systems of organs, two peculiar sets of nervous filaments, one 

 of which serves to conduct the currents from their centre 

 towards the periphery, whereas the other must be instrumen- 

 tal in conducting them back towards the centre. — On the 

 other hand, we have to show how an electrical current can 

 pervade a nerve, or any other organized substance of equal 

 conducting power, without being dissipated in the rest of the 

 organs. 



As to the former point, M. Matteucci adverts to different 

 circumstances which may assist us in our investigations ; for 

 instance, the peculiar functions of the well-known two diffe- 



