This led to his working as an assistant to Professor Johan Erik Vesti Boas at the Agricultural University's zoological laboratory, as both a teacher and researcher.
While teaching, he resumed his scientific studies, first at the Carlsberg Foundation's Biological Institute with Albert Fischer, and later at Stockholm University (1934-1936), where he earned his doctorate with the thesis, Entwicklungsphysiologische Studien über Spongilla lacustris (Studies of the developmental physiology of Spongilla lacustris).
His interest in developmental physiology led to a series of lectures at Copenhagen University, and the possibility of a chair there, but war intervened.
He introduced cytology and experimental embryology, and the courses included histology and evolutionary theory.
[1] Alongside his teaching and research work, he became more and more preoccupied with philosophical and religious problems which needed to be related to the biological basis of life.