▁He ▁stood ▁high ▁in ▁este em ▁in ▁Amsterdam ▁and ▁in ▁ 1 6 3 7 , ▁was ▁inspect or ▁of ▁the ▁medical ▁college ▁there . ▁Following ▁an ▁inv itation ▁( August ▁ 1 6 3 9 ) ▁from ▁their ▁Professor ▁of ▁An atom y ▁and ▁Bot any , ▁van ▁der ▁L inden ▁joined ▁the ▁University ▁of ▁Fran ek er , ▁giving ▁his ▁intro duct ory ▁lecture ▁on ▁De ▁med ico ▁fut uro ▁necess ari is ▁( On ▁ 2 6 ▁November ▁ 1 6 3 9 ) ▁then ▁en rolled ▁in ▁the ▁registers ▁on ▁ 2 ▁December ▁ 1 6 3 9 . ▁An ▁important ▁fruit ▁of ▁his ▁studies ▁was ▁the ▁medical ▁bibli ography ▁De ▁Med ici ▁lib ri ▁du o ▁script is ▁( G arrison - M orton ▁ 6 7 4 4 ), ▁which ▁was ▁en larg ed ▁through ▁ 3 ▁ed itions ▁while ▁he ▁lived , ▁and ▁then ▁by ▁later ▁authors . ▁ ▁During ▁his ▁twelve - year ▁ten ure ▁in ▁Fran ek er ▁he ▁led ▁dis sections , ▁and ▁was ▁appointed ▁Director ▁of ▁the ▁College ▁( 1 6 4 3 / 1 6 4 4 ). ▁In ▁ 1 6 4 9 ▁he ▁rejected ▁a ▁professor ship ▁at ▁the ▁University ▁of ▁U tre cht , ▁but ▁subsequently ▁accepted ▁a ▁new ▁appointment ▁at ▁the ▁University ▁of ▁Le iden ▁as ▁professor ▁of ▁practical ▁medicine ▁( 1 6 5 1 ). ▁As ▁head ▁of ▁the ▁Le iden ▁University ▁Hospital , ▁he ▁also ▁worked ▁with ▁Francis cus ▁Syl vi us . ▁L inden