He returned to Berlin in the same year and focused on chemistry.

He received his PhD for work with August Wilhelm von Hofmann in Berlin and became assistant of Karl Friedrich August Rammelsberg at Charlottenburg and in 1883 of Adolf von Baeyer at the University of Munich, where, after his habilitation in 1891, he became associate professor for chemistry.

The Eidgenössische Technische Hochschule Zürich (ETH Zurich) appointed him professor in 1893, where he stayed until a severe illness forced him to retire from the position in 1905.

He suffered from limited control of his right arm and severe headache for the rest of his life.

In the last years of his life he lived at Ponte Tresa, Ticino.