S^cT, IIL] Theory mid Practice of Physic. 3S^ 



rather docs not exist, unless exeiting powers arc 

 applied; for, if tlioy be entirely witlidrawii, deatli 

 as certainly ensues as when excitability is coiismned 

 hy the excessive application of ihein ; life is there- 

 fore a forced slate. Excitement may be in just 

 measnre, or too great, or too small. St imuH ap|)ned 

 in due proportion produce that just (le,i;ree of ex- 

 citement wliich constitutes the «tate of health. If 

 the stimuli be diiiiinished below the healthy pro-, 

 portion, he supposed the excitability to a/:eumu- 

 late; if increcLsed beyond this proportion, to be 

 expended; and on these opposite states he at- 

 tempted to found a theory of diseases, denominat- 

 hig the ibrmer direct, the latter indirect debilitv. 

 Diseases he divided into tv.o classes, slJttnic and 

 astJienic, or such as arise from increased and from 

 diminished excitement. He believed no aq-ent on 

 the living body could properly receive the title of 

 scdatiie; and insisted that every ])o\ver tiiat acts 

 on such a body is stimulant, or produces excite- 

 ment by expending excitabilit\\ Whatever powers 

 therefore may be employed, and however they may 

 vary from sucii as are habitually applied to produce 

 due excitement, they can onlv' weaken the system, 

 by urging it into too much motion, or saiVering it 

 to sink into languor. He is supposed to have in- 

 cluded both the nervous and muscular powers un- 

 der tlie term of excitability ; yet he did not con- 

 sider the excitability as a pro}>erty residing in and 

 depending upon the mechanism of particular parts, 

 but as a iniiform undivided property, pcrvatling 

 the whole system, which cannot be affected in any 

 one part without being atfected in a siuiilar nianuer 

 in every other. 



