, ▁the ▁rest ▁having ▁been ▁burn ed ▁shortly ▁after ▁publication . ▁In ▁the ▁second ▁edition ▁V es al ius ▁published ▁that ▁the ▁sept um ▁was ▁indeed ▁water proof , ▁discover ing ▁( and ▁naming ), ▁the ▁mit ral ▁val ve ▁to ▁explain ▁the ▁blood ▁flow . ▁ ▁V es al ius ▁believed ▁that ▁card iac ▁syst ole ▁is ▁synchron ous ▁with ▁the ▁ar ter ial ▁pul se . ▁ ▁He ▁not ▁only ▁verified ▁Est ienne ' s ▁find ings ▁on ▁the ▁val ves ▁of ▁the ▁he p atic ▁ve ins , ▁but ▁also ▁described ▁the ▁a zy g os ▁ve in , ▁and ▁discovered ▁the ▁canal ▁which ▁passes ▁into ▁the ▁fet us ▁between ▁the ▁um bil ical ▁ve in ▁and ▁v ena ▁c ava . ▁ ▁N erv ous ▁system ▁▁▁ ▁V es al ius ▁defined ▁a ▁n erve ▁as ▁the ▁mode ▁of ▁transm itting ▁sens ation ▁and ▁motion ▁and ▁thus ▁ref uted ▁his ▁contempor aries ' ▁claims ▁that ▁lig aments , ▁tend ons ▁and ▁ap one u ros es ▁were ▁three ▁types ▁of ▁n erve ▁units . ▁▁▁ ▁He ▁believed ▁that ▁the ▁brain ▁and ▁the ▁nerv ous ▁system ▁are ▁the ▁center ▁of ▁the ▁mind ▁and ▁em otion ▁in ▁contrast ▁to ▁the ▁common ▁Arist ot elian ▁belief ▁that ▁the ▁heart ▁was ▁the ▁center ▁of ▁the ▁body . ▁He ▁corresponding ly ▁believed ▁that ▁n erves ▁themselves ▁do ▁not ▁origin ate ▁from ▁the ▁heart , ▁but ▁from ▁the ▁brain . ▁▁ ▁Upon ▁studying ▁the ▁opt ic ▁n erve , ▁V es al ius ▁came ▁to