10 HISTOBIOAL SKETCH. CHAP. I- 



Animal Electricity ; and the next question that arose 

 was that of the origin of the power in the Voltaic 

 circle, whether hy a contact or hy chemical action. 

 A fresh subject of controversy was now introduced, 

 and one which has continued up to the present 

 day. 



In 1806, Davy astonished the scientific world by 

 his well-known discovery of the decomposition of the 

 alkalies by means of the Voltaic battery, and esta- 

 blished the important fact, that acids were evolved 

 at one pole and alkalies at the other pole of the 

 battery, from whence arose the phrase polar decom- 

 position. Wollaston immediately seized upon the 

 idea, that animal secretions were effected by the 

 agency of a similar electric power, and published an 

 important Paper containing his views. As I have 

 quoted this Paper in the chapter on the Secretions, 

 I shall only now allude to it. Dr. T. Young* also 

 entertained views somewhat similar to those of 

 Wollaston, but being unsupported by direct ex- 

 perimental evidence, they need not be detailed. 



Oersted's celebrated discovery in 1820, that a 

 magnetic needle was influenced by an electric 

 current, led to the introduction of the galvanometer ; 

 and in 1827, Nobiu, in his endeavours to ascertfun 

 whether this new instrument could equal the delicacy 

 of the galvanoscopic frog in its indications of elec- 

 trical action, established the important fact, that 

 a current of electricity existed in the limbs of the 

 <> Medical Literature, p. 111. 



