3 o8 DISEASES SECT. XXXIII. i. 4 . 



fenforial fpirit , and the ftimuli from external bodies have no 

 effect on the exhaufted fenforial power, and a delirium like a 

 dream is the confequence. At length the internal ilimuli ceale to 

 excite fufficient irritation, and the fecretions are either not pro- 

 duced at all, or too parfimonious in quantity. Amongft thefe 

 the fecretion of the brain, or production of the fenforial power, 

 becomes deficient, till at laft all fenforial power ceafes, except 

 what is juft neceflary to perform the vital motions, and a ftupor 

 fucceeds ; which is thus owing to the fame caufe as the prece- 

 ding delirium exerted in a greater degree. 



This kind of delirium is owing to a fufpenfion of volition, and 

 to the difobedience of the fenfes to external ftimuli, and is always 

 occafioned by great debility, or paucity of fenforial power ; it 

 is therefore a bad fign at the end of inflammatory fevers, which 

 had previous arterial flrength, as rheumatifm, or pleurify, as it 

 (hews the prefence of great exhauftion of fenforial power in a 

 fyftem, which having lately been expofed to great excitement, is 

 not fo liable to be ftimulated into its healthy aclion, either by 

 additional ftimulus of food and medicines, or by the accumula- 

 tion of fenforial power during its prefent torpor. In inflamma- 

 tory fevers with debility, as thofe termed putrid fevers, deliri- 

 um is fometimes, as well as ftupor, rather a favourable fign ; as 

 lefs fenforial power is wafted during its continuance (fee Clafs 

 II. i. 6. 8.), and the conftitution not having been previoufly ex- 

 pofed to excefs of ftimulation, is more liable to be excited after 

 previous quiefcence. 



When the fum of general pleafurable fenfation becomes too 

 great, another kind of delirium fupervenes, and the ideas thus 

 excited are miftaken for the irritations of external objefts : fuch 

 a delirium is produced for a time by intoxicating drugs, as fer- 

 mented liquors, or opium : a permanent delirium of this kind is 

 fometimes induced by the pleafures of inordinate vanity, or by 

 the enthufiaftic hopes of heaven. In thefe cafes the power of 

 volition is incapable of exertion, and in a great degree the exter- 

 nal fenfes become incapable of perceiving their adapted ftimuli, 

 becaufe the whole fenforial power is employed or expended on 

 the ideas excited by pleafurable fenfation. 



This kind of delirium is diftinguifhed from that which at- 

 tends the fevers above mentioned from its not being accompani- 

 ed with general debility, but fimply with excefs of pleafurable 

 fenfation ; and is therefore in forne meafure allied to madnefs 

 or to reverie ; it differs from the delirium of dreams, as in this 

 the-power of volition is not totally fufpended, nor are the fenfes 

 precluded from external ftimulation ; there is therefore a degree 

 of confiftency 3 in this kind of delirium, and a degree of attentioa 



