SENSATION ANI> ITS OBJECTS. 



it will be easy to understand, that what is void 

 of thought and of reason cannot be the cause 

 of thought and of reason ; that although sensa- 

 tion, any more than ratiocination, cannot exist 

 without an instrument or organ; the organ is 

 not the cause either of sensation or ratiocina- 

 tion ; although right thinking and feeling may 

 not take place without a right disposition of 

 body, a right disposition of body is not as a 

 consequence, the efficient cause of right think- 

 ing. The body, it has been well observed by a 

 celebrated divine, may hinder thought, but 

 cannot effect it ; the faculties of the soul like 

 the sun, may be obscured and eclipsed by an 

 interposing body, but as soon as the obstruction 

 is removed, the light will shine out again in 

 full lustre. 



What are the individual properties of which 

 the different bodies are composed, whieh, im- 

 pressed upon the organs of sense, excite the 

 different sensations, is a physical not a physio* 

 logical question, and is more cognisable by 

 the natural philosopher, than by the physio- 

 logist. 



It is the province of the chemist to analyse the 

 materials of which the different kinds of food 

 are composed ; to ascertain the parts which 

 constitute the difference, by which one species 

 of food is, in its nature, different from the rest; 



