DEPEND ON CHEMICAL CHANGES. 11 



and is converted into unorganised, amorphous com- 

 pounds ; in a word, no waste occurs in vegetables. 

 Waste, in the animal body, is a change in the state 

 or in the composition of some of its parts, and 

 consequently is the result of chemical actions. 



The influence of poisons and of remedial agents 

 on the living animal body evidently shews that the 

 chemical decompositions and combinations in the 

 body, which manifest themselves in the phenomena 

 of vitality, may be increased in intensity by chemical 

 forces of analogous character, and retarded or put 

 an end to by those of opposite character ; and that 

 we are enabled to exercise an influence on every 

 part of an organ by means of substances possessing 

 a well-defined chemical action. 



As, in the closed galvanic circuit, in consequence 

 of certain changes which an inorganic body, a metal, 

 undergoes when placed in contact with an acid, a 

 certain something becomes cognizable by our senses, 

 which we call a current of electricity ; so, in the 

 animal body, in consequence of transformations and 

 changes undergone by matter previously constituting 

 a part of the organism, certain phenomena of motion 

 and activity are perceived, and these we call life, or 

 vitality. 



The electrical current manifests itself in certain 

 phenomena of attraction and repulsion, which it 

 excites in other bodies naturally motionless, and by 

 the phenomena of the formation and decomposition 

 of chemical compounds, which occur everywhere, 



