Complex sentence: After graduation in 1907, he enrolled at the Faculty of Medicine in Bucharest, In 1908 he enrolled at the University of Bucharest, Faculty of Natural Sciences, where he graduated in 1912.
Split into simpler sentences: After graduation in 1907, he enrolled at the Faculty of Medicine in Bucharest. The next year, he enrolled at the University of Bucharest, Faculty of Natural Sciences, from which he graduated in 1912.