3 o SENSITIVE MOTIONS. SECT. VIII. 2. r. 



of thefe fenfations, now vividly recur before us by their con- 

 nexion with thefe fenfations themfelves. So the fair fmiling 

 virgin, that excited your love by her prefence, whenever that 

 fenfation recurs, rifes before you in imagination ; and that with 

 all the pleafmg circumftances that had before engaged your at- 

 tention. And in fleep, when you dream under the influence of 

 fear, all the robbers, fires, and precipices, that you formerly 

 have feen or heard of, arife before you with terrible vivacity. All 

 thefe fenfuai motions, like the mufcular ones above mentioned, 

 are performed with flrength and velocity in proportion to the 

 energy of the fenfation of pleafure or pain, which excites them, 

 and the quantity of fenforial power. 



II. i Many of thefe mufcular motions above defcribed, that 

 are moil frequently excited by our fenfations, are neverthelefs 

 occafionally cauiable by volition ; for we can fmile or frown 

 fpontaneoufly, can make water before the quantity or acrimony 

 of the urine produces a difagreeable fenfation, and can volunta- 

 rily mafticate a naufeous drug, or fvvallow a bitter draught, 

 though our fenfation would ftrongly difluade us. 



2. In like manner the fenfuai motions, or ideas, that are mod 

 frequently excited by our fenfations, are neverthelefs occafion- 

 ally caufable by volition, as we can fpomaneoufly call up our 

 laft night's dream before us> tracing it indu trioufly itep by (tep 

 through all its variety of fcenery and tranfa6Hons ; or can vol- 

 untarily examine or repeat the ideas, that have been excited by 

 our difguit or admiration. 



III. i. Innumerable trains or tribes of motions are aflbciated 

 with thefe fenfitive mufcular motions above mentioned ; as when 

 a drop of water falling into the wind-pipe difagreeably affefts 

 the air-veflels of the lungs, they are excised into violent a<ftion ; 

 and with thefe fenfitive motions are aflbciated the adions of the 

 pedoral and intercoital mufcles, and the diaphragm ; till by 

 their united and repeated fucceffions the drop is returned 

 through the larinx. The fame occurs when any thing difagree- 

 ably affefts the noftrils, or the (lomach, or the uterus ; variety 

 of mufcles are excited by aflbciation into forcible aftion, not to 

 be fupprefTed by the utmofl efforts of the will ; as in fneezing, 

 vomiting, and parturition. 



2. In like manner with thefe fenfitive fenfuai motions, or ideas 

 of imagination, are aflbciated many pther trains or tribes of 

 ideas, which by fome writers of metaphyfics have been clafled 

 under the terms of refemblance, caufation and contiguity ; and 

 will be more fully treated of hereafter. 



SECT, 



