Complex sentence: In his fourth year of study Krebs had decided to either pursue a higher degree in organic chemistry or study medicine, receiving a scholarship to attend Washington University School of Medicine in St. Louis, he chose the latter.
Split into simpler sentences: In his fourth year of study Krebs had decided to either pursue a higher degree in organic chemistry or study medicine. Receiving a scholarship to attend Washington University School of Medicine in St. Louis, he chose the latter.