PREFACE. IX 



two kinds of diseased actions comprehended under one 

 word; which have each their different proximate 

 cause. 



In Sect. XXXIX. 8. 4. and in Class II. 1. 1. 1. we 



have endeavoured to give names to four links of ani- 

 mal causation, which conveniently apply to the classifi- 

 cation of diseases; thus in common nictitation, or wink- 

 ing with the eyes without our attention to it, the in- 

 creased irritation is the proximate cause; the stimulus of 

 the air on the dry cornea, is the remote cause; the clos- 

 ing of the eye-lid is the proximate effect; and the dif- 

 fusion of tears over the eye-ball is the remote effect. 

 In some cases two more links of causation may be in- 

 troduced; one of them may be termed the pre-remote 

 cause; as the warmth or motion of the atmosphere,, 

 which causes greater exhalation from the cornea. And 

 the other the post-remote effect; as the renewed pellu- 

 cidity of the cornea; and thus six links of causation 

 may be expressed in words. 



But if amid these remote links of animal causation 

 any of the four powers or faculties of the sensorium be 

 introduced, the reasoning is not just according to the 

 method here proposed; for these powers of the senso- 

 rium are always the proximate causes of the contrac- 

 tions of animal fibres; and therefore in true language 

 cannot be termed their remote causes. From this cri- 

 terion it may always be determined, whether more dis- 

 eases than one are comprehended under one name; a 

 circumstance which has much impeded the investiga- 

 tion of the causes, and cures of diseases. 



Thus the term fever is generally given to a collec- 

 tion of morbid symptoms; which are indeed so many 

 VOL. IT. b 



