 He made his doctoral thesis in biology and botany, on shoot architecture of mangrove trees and Eugen Warming served as faculty opponent in October 1903.Schmidt then more or less switched to marine zoology, working 1902–1909 part-time for the Botanical Institute of the University of Copenhagen, part-time for the "Danish Commission for Investigation of the Sea".In 1909, he was made head of the department of physiology at the Carlsberg Laboratory, a post he held until his early death.