Wemustknow, therefore, thatalthoughthehumansoulisunitedtothewholebody, ithas, nevertheless, itsprincipalseatinthebrain, wherealoneitnotonlyunderstandsandimagines, butalsoperceives; andthisbythemediumofthenerves, whichareextendedlikethreadsfromthebraintoalltheothermembers, withwhichtheyaresoconnectedthatwecanhardlytouchanyoneofthemwithoutmovingtheextremitiesofsomeofthenervesspreadoverit; andthismotionpassestotheotherextremitiesofthosenerveswhicharecollectedinthebrainroundtheseatofthesoul, , whichisintimatelyconjoinedwiththebrain, , arecalledperceptionsofthesenses (SENSUUMPERCEPTIONES), or, aswecommonlyspeak, sensations (SENSUS).
; and, first, oftheinternal, thatis, oftheaffectionsofthemind (passions), andthenaturalappetites.
