8 LECTURE I. 



There was a time when medical men 

 entertained so determined a dislike to the 

 word theory, that they could scarcely to- 

 lerate the term. If any such remain, I 

 would beg them to reflect that hypothesis 

 and theory are the natural and inevitable 

 result of thinking ; so that if they refuse to 

 allow of any theory, they must prohibit all 

 thought. 



The antipathy which some have enter- 

 tained to the term theory, has arisen from its 

 misapplication. For opinions drawn from 

 very partial views of subjects, sometimes 

 having no foundation on facts ; opinions 

 formed by processes of mind, similar to 

 those which occur in dreaming, when law- 

 less imagination produces combinations and 

 associations without any reference to reali- 

 ties ; opinions, as unlike what I should un- 

 derstand by theory as darkness is to light, 

 have nevertheless been often proposed as 

 theories and so denominated. That such 

 foolish speculations, such waking dreams, 

 will mislead and deceive us, cannot be 

 doubted; and hence has arisen the preju- 



