SSCT. XIL OF STIMULUS AND EXERTION. 63 



formed In lefs time, and with Jhorter intervals. 5. 

 5. Laft fituation of the fibres continues after contrac- 

 tion. 6. Contraction greater than ufual induces plea- 

 fure or pain. 7. Mobility of the fibres uniform. 

 Quantity cf fenforial power fluctuates. Constitutes 

 excitability. If. Of fenforial exertion. \.Animal 

 motion includes Jlimulus^ fenforial power ^ and contrac- 

 tile fibres. The fenforial faculties aft feparately or 

 conjointly. Stimulus of four kinds. Strength and 

 iveaknefs defined. Senforial power perpetually exkauft- 

 *d and renewed. Weakncfs from defeci of ftimulus* 

 From defeci of fenforial power , the dirett and indired 

 debility of Dr. Brown. Why we become warm in Bux- 

 ion bath after a time^ and fee well after a time in a 

 darkifh room, fibres may aft violently , or with their 

 wl^ole force ', and yet feebly. Great exertion in inflam- 

 mation explained. Great ?nufcular force of fome in- 

 fane people 2. Occqfional accumulation cf fenforial 

 power in mufcles fubjeft to conft ant Jlimulus. In ani- 

 mals Jleeping in winter. In eggs, feeds, fchirrous tu- 

 mours, tendons y bones. 3. Great exertion introduces 

 pleafure or pain. Inflammation. Libration of the 

 fyjlem between torpor and activity. Fever-Jits. 4. 

 Defire and averfion introduced. Excefs of volition 

 tures fevers. III. Of repeated ftimulus. i. A 

 Jlimulus repeated too frequently lofes effect. As opium, 

 wine, grief. Hence old age. Opium and aloes in 

 fmall dofes. 2. Ajtimulus not repeated too frequently 

 does not lofe effect. Perpetual movement of the vital 

 organs. 3. Ajlimulus repeated at uniform times produces 

 greater effecl. Irritation combined 'with affbciation. 

 4. Ajlimulus repeated frequently and uniformly may 

 be withdrawn, and the action of the organ will con- 

 tinue. Hence the bark cures agues 9 andftrengthens 

 weak conjlitutions . 5. Defeci, of Jlimulus repeated at 

 certain intervals caufes fever-Jits. 6. Stimulus long 

 applied ceafes to aft afecond time. 7. If a Jlimulus 

 excites fenjation in an organ not ufually excited into fen- 



