510 PRACTICE OF PHYSIC. 



son for comprehending the morositates in general under the ve- 

 sanioe, considered as primary diseases. 



The limitation, therefore, of the class of Vesanise to the le- 

 sions of our judging faculty, seems from every consideration to 

 be proper. 



The particular diseases to be comprehended under this class, 

 may be distinguished according as they affect persons in the 

 time of waking or sleeping. Those which ^affect men awake, 

 may again be considered, as they consist in an erroneous judg- 

 ment, to which I shall give the appellation of Delirium ; or as 

 they consist in a weakness or imperfection of judgment, which I 

 shall name Fatuity. I begin with the consideration of Delirium. 



MDXXX. As men differ greatly in the soundness and force 

 of their judgment, so it may be proper here to ascertain more 

 precisely what error or imperfection of our judging faculty is to 

 be considered as morbid, and to admit of the appellations of 

 Delirium and Fatuity. In doing this, I shall first consider 

 the morbid errors of judgment under the general appellation of 

 Delirium, which has been commonly employed to denote every 

 mode of such error. 



MDXXX I. As our judgment is chiefly exercised in discern- 

 ing and judging of the several relations of things, I apprehend 

 that delirium may be defined to be, In a person awake, a false 

 or mistaken judgment of those relations of things, which, as oc- 

 curring most frequently in life, are those about which the gen- 

 erality of men form the same judgment ; and particularly when 

 the judgment is very different from what the person himself had 

 before usually formed. 



" The perceptions of men are nearly similar : for this rea- 

 son, there is also a similarity in the perception of relation. 

 Simple perceptions and their relations are the materials on which 

 the intellect is exercised. They are laid up in the mind by as- 

 sociations, and it is in following these associations that the mind 

 brings back before it the relations which it is to judge of. 



" But if the perception of relations is similar, so will the as- 

 sociations be in common with the most part of men ; and as the 

 perceptions, relations, and associations are founded on the na- 

 ture of things, so the judgments of men will be similar, and in 



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