▁the ▁Free ▁University ▁Berlin . ▁He ▁entered ▁P enn ▁medical ▁school ▁in ▁the ▁Fall ▁of ▁ 1 9 6 0 , ▁but ▁discovered ▁that ▁he ▁was ▁more ▁interested ▁in ▁research , ▁particularly ▁after ▁sp ending ▁the ▁summer ▁of ▁ 1 9 6 2 ▁carrying ▁out ▁research ▁on ▁protein ▁b ios yn thesis ▁under ▁the ▁super vision ▁of ▁Sydney ▁B ren ner ▁at ▁the ▁Labor atory ▁of ▁M ole cular ▁Bi ology , ▁Cambridge , ▁England . ▁He ▁decided ▁to ▁purs ue ▁a ▁Ph . D . ▁and ▁became ▁one ▁of ▁P enn ' s ▁first ▁M . D .- Ph . D . ▁students , ▁working ▁with ▁Robin ▁Hoch str asser ▁on ▁mole cular ▁spect ro sc opy ▁of ▁single ▁cry st als ▁of ▁h eme ▁prote ins . ▁He ▁received ▁his ▁M . D . ▁in ▁ 1 9 6 4 ▁and ▁his ▁Ph . D . ▁in ▁ 1 9 6 7 . ▁After ▁finishing ▁his ▁Ph . D . ▁research , ▁he ▁was ▁draft ed ▁into ▁the ▁military ▁and ▁chose ▁to ▁ful fill ▁his ▁military ▁oblig ation ▁as ▁a ▁medical ▁officer ▁in ▁the ▁ ▁United ▁States ▁Public ▁Health ▁Service , ▁where ▁he ▁could ▁conduct ▁research ▁at ▁the ▁National ▁Instit utes ▁of ▁Health . ▁ ▁Research ▁career ▁E aton ▁has ▁spent ▁his ▁entire ▁career ▁at ▁the ▁N I H ▁after ▁arriv ing ▁as ▁a ▁medical ▁officer ▁in ▁the ▁Public ▁Health ▁Service ▁in ▁January ▁ 1 9 6 8 , ▁leaving ▁only ▁once ▁for ▁a ▁significant ▁period ▁of ▁time ▁to ▁teach ▁physical