Several years later, he was stationed at the Imperial Health Office in Berlin, where he was exposed to the latest developments of Emil von Behring (1854–1917).
In 1897, under the direction of Robert Koch (1843–1910), he along with Georg Gaffky (1850–1918) and Richard Pfeiffer (1858–1945), researched the bubonic plague in Bombay.
After his return to Germany, he spent six years as a military physician in Würzburg, where in 1898 he gained his habilitation in hygiene at the university.
In 1906, he became an honorary professor, and three years later was appointed as Ministerialrat and Medizinalreferent in the Ministry of the Interior, subsequently becoming head of Bavarian Aid Services.
[citation needed] For most of his career he dealt with the issue of controlling outbreaks of disease, in the civilian as well as in the military sector.