SECT. XIX. 7. O F R E V E R I E. 26$ 



to fupprefs the other trains of ideas, which might 

 interrupt thefe feeble fenfations. Hence in the pre- 

 fent hiftory the ftrongeft ftimuli were not perceived, 

 except when the faculty of volition was exerted on 

 the organ of fenfe ; and then even common ftimuli 

 were fometimes perceived ; for her mind was fo 

 ftrenuoufly employed in purfuing its own trains of 

 voluntary or fenfitive ideas, that no common ftimuli 

 could fo far excite her attention as to difunite them; 

 that is, the quantity of volition or of fenfation al- 

 ready exifting was greater than any, which could 

 be produced in confequence of common degrees of 

 ftimutation. But the few ftimuli of the tuberofe, 

 and of the tea, which fhe did perceive, were fuch, 

 as accidentally comcided with the trains of thought, 

 which were palling in her mind ; and hence did not 

 difunite thofe trains, and create furprife. And their 

 being perceived at all was owing to the power of 

 volition preceding or coinciding with that of irri- 

 tation. 



This explication is countenanced by a fact men- 

 tioned concerning a fomnambulift in the Laufanne 

 Tranfa&ions, who fcmetimes opened his eyes for a 

 fhort time to examine, where he was, or where his 

 ink-pot (food, and then fhut them again, dipping 

 his pen into the pot every now and then, and wri- 

 ting on, but never opening his eyes afterwards, al- 

 though he wrote on from line to line regularly, and 

 corrected fome errors of the pen, or in fpelling: 

 fo much eafier was it to him to refer to his ideas of 

 the pofitions of things, than to his perceptions of 

 them. 



7. The afibciated motions perfifted in their ufual 

 channel, as appeared by the combinations of her 

 ideas, and the ufe of her mufcles, and the equality 

 of her pulfe ; for the natural motions of the arte- 

 rial fyftem, though origina'ly excited like other 

 motions by ftimulus, feem in part to continue by 



their 





