Complex sentence: After graduation Dr. Stahl returned to Puerto Rico where he set up his own medical practice in the city of Bayamón; however, outside work his love of nature lead him to conduct investigations and experiments in the fields of ethnology, botany, and zoology.
Split into simpler sentences: After graduation Dr. Stahl returned to Puerto Rico where he set up his own medical practice in the city of Bayamón. Outside work his love of nature lead him to conduct investigations and experiments in the fields of ethnology, botany, and zoology.