CLASS I. i, r. DISEASES, c. 9 



CLASS I. 



DISEASES OF IRRITATION. 



ORDO I. 



Increafed Irritation. 



GENUS I. 

 With increafed aclions of the Sanguifirous Syjlem, 



THE irritability of the whole, or of part, of our fyftem is per- 

 petually changing ; thefe viciffitudes of irritability and of inir- 

 ritability are believed to depend on the accumulation or exhauf- 

 tion of the fenforial power, as their proximate caufe ; and on the. 

 difference of the prefent ftimulus, and of that which we had 

 previoufly been accuftomed to, as their remote caufe. Thus a 

 fmaller degree of heat produces pain and inflammation in our 

 hands, after they have been for a time immerfed in fnow ; 

 which is owing to the accumulation of fenforial power in the 

 moving fibres of the cutaneous vefiels during their previous qui- 

 efcftice, when they were benumbed with cold. And we feel 

 ourfelves cold in the ufual temperature of the atmofphere on 

 coming out of a warm room ; which is owing to the exhauftion 

 of fenforial power in the moving fibres of the veffels of the (kin. 

 by their previous increafed activity, into which they were exci- 

 ted by unufual heat. 



Hence the cold fits of fever are the occafion of the fucceedmg 

 hot ones ; and the hot fits contribute to occafion in their turn 

 the fucceeding cold ones. And though the increafe of ftimulus, 

 as of heat, exercife, or diftention, will produce an increafed ac- 

 tion of the ftimulated fibres ; in the fame manner as it is pro- 

 duced by the increafed irritability which was occafioned by a 

 previous defect of ftimulus ; yet as the excelles of irritation from 

 the ftimulus of external things are more eafily avoided than the 

 deficiencies of it ; the difeafes of this country, except thofe which 

 are the confequences of drunkennefs, or of immoderate exercife, 

 more frequently begin with torpor than with orgafm j that is* 

 with inactivity of fome parts, or of the whole of the fyftem, and 

 confequent coldnefs, than with increafed -activity, and confe- 

 quent heat. 



If the hot fit be the confequence of the cold one, it may be 

 aflced if they are proportionate to each other : it ft probable that 



VOL. II. C the* 



