Krehl inspired Morawitz in his studies of blood-related pathology. In 1907 he completed a dissertation on blood circulation (for his Habilitation), and he was appointed in the same year as chief clinician of the University clinic at Freiburg im Breisgau.
Krehl's work on blood-related pathology influenced Morawitz's research, leading to a dissertation on blood circulation in 1907, which was followed by his appointment as chief clinician of the University clinic at Freiburg im Breisgau.