▁born ▁in ▁Wür zburg , ▁Bav aria ▁in ▁ 1 8 2 6 , ▁and ▁he ▁entered ▁the ▁University ▁of ▁Wür zburg ▁as ▁a ▁student ▁in ▁ 1 8 4 5 . ▁After ▁taking ▁his ▁degree ▁in ▁ 1 8 5 1 , ▁he ▁spent ▁some ▁time ▁in ▁trav elling ▁in ▁Italy ▁and ▁Sic ily , ▁before ▁returning ▁to ▁W ur zburg ▁as ▁Priv at do zent ▁in ▁ 1 8 5 4 . ▁In ▁ 1 8 5 5 , ▁he ▁was ▁appointed ▁extraordinary ▁professor ▁of ▁an atom y ▁at ▁the ▁University ▁of ▁J ena , ▁and ▁in ▁ 1 8 5 8 , ▁he ▁became ▁the ▁ordinary ▁professor , ▁where ▁after ▁ 1 8 6 5 , ▁his ▁former ▁student ▁and ▁fellow - worker ▁Ernst ▁H ae ck el ▁was ▁professor ▁of ▁zo ology . ▁ ▁In ▁ 1 8 7 3 , ▁Gegen ba ur ▁was ▁appointed ▁to ▁Heidel berg , ▁where ▁he ▁was ▁professor ▁of ▁an atom y ▁and ▁director ▁of ▁the ▁An atom ical ▁Institute ▁until ▁his ▁ret irement ▁in ▁ 1 9 0 1 . ▁He ▁was ▁elected ▁a ▁Foreign ▁Honor ary ▁Member ▁of ▁the ▁American ▁Academy ▁of ▁Arts ▁and ▁Sciences ▁in ▁ 1 8 9 6 . ▁He ▁died ▁on ▁ 1 4 ▁June ▁ 1 9 0 3 , ▁at ▁Heidel berg . ▁ ▁Imp act ▁ ▁The ▁work ▁by ▁which ▁Gegen ba ur ▁is ▁best ▁known ▁is ▁his ▁Grund r iss ▁der ▁ver gleich enden ▁An atom ie ▁( Le ip zig , ▁