IN THE ANIMAL ORGANISM. 217 



attraction and repulsion, which we must ascribe to 

 the disturbance of the equilibrium in the electric 

 or magnetic force ; and when this equilibrium is 

 restored, the restoration is accompanied by the de- 

 velopement of light and heat, its never-failing com- 

 panions. 



All these remarkable phenomena are produced 

 by the chemical action which the zinc and the acid 

 exert on each other; they are accompanied by a 

 change in form and structure, which both undergo. 



The acid loses its chemical character ; the zinc 

 enters into combination with it. The manifestations 

 of force produced in the wire are the immediate 

 consequence of the change in the properties of the 

 acid and the metal. 



One particle of acid after another loses its pecu- 

 liar chemical character ; and we perceive that in 

 the same proportion the wire acquires a chemical, 

 mechanical, galvanic, or magnetic force, whatever 

 name be given to it. According to the number of 

 acid particles which in a given time undergo this 

 change, that is, according to the surface of the zinc, 

 the wire receives a greater or less amount of these 

 forces. 



The continuance of the current of force depends 

 on the duration of the chemical action ; and the 

 duration of the latter is most closely connected with 

 the carrying away, by conduction, of the force. 



If we check the propagation of the current of 

 force, the acid retains its chemical character. If 



