LECTURE I. 33 



animal matter, as magnetism is to iron, and 

 as electricity is to various substances with 

 which it may be connected. Mr. Hunter 

 dolibtless thought, and I believe most per- 

 sons do think, that in magnetic and electric 

 motions, a subtile invisible substance, of a 

 very quickly and powerfully mobile nature, 

 puts in motion other bodies which are evi- 

 dent to the senses, and are of a nature more 

 gross and inert. To be as convinced as 1 

 am of the probability of Mr. Hunter's 

 Theory as a cause of irritability, it is, I am 

 aware, necessary to be as convinced as I 

 am that electricity is what I have now 

 supposed it to be, and that it pervades all 

 nature. To obtain this conviction it is ne- 

 cessary that the facts connected with this 

 subject should be attentively considered ; 

 but for such an examination I have no time ; 

 neither would it be considered as suitable 

 to the general design of these lectures. 



Whatever notions philosophers may be 

 pleased to form respecting matter in ge- 

 neral, it does not appear to me that our 

 physiological opinions can be affected by 

 their decisions. Of the matter which for 



D ' 



