HISTORY OF GALVANISM. 43 



or controversy. Animal electricity, as produced in 

 the original experiments of Galvani, and after- 

 wards in those of Valli, Fowler, Volta, and others, 

 was now admitted to depend upon nothing adhe- 

 rent in, or attached to, the animal body, but upon 

 an agent, called into action by external causes, and 

 manifesting itself in consequence of the delicate 

 sensibility of the nervous and muscular systems. 

 This agent was now generally recognized as being 

 identical with electricity, conducted by the same 

 substances, possessing the same properties, and, in 

 short, subject to the same physical laws. It was 

 conjectured, that the apparent difference between 

 electricity, as excited by the machine and by the 

 pile, depended upon the different states of intensity 

 in which they exist ; the electricity of the machine 

 being in a much higher state than that of the 

 pile, although this latter is generally disengaged in 

 greater quantity. This may be regarded as the 

 state of the science in 1801 ; from this time, until 

 the grand discovery of Sir II. Davy, which I 

 have marked out as the third era, the attention 

 of the different experimentalists, who devoted 

 themselves to this department of natural philoso- 

 phy, was partly directed to improving or modify- 

 ing the apparatus, and partly to hypothetical dis- 

 cussions, respecting the nature of the action, and 

 its connexion with chemical affinity. 



The effect of the size of the plates in the gal- Blot's ob- 

 vanic pile had been already observed by Fourcroy 

 and others, and was now more particularly noticed 



