Complex sentence: Although he never attained the title of "full professor" during his career, he remained at Halle as a lecturer, and in the meantime, worked at a private medical practice and was devoted to many social and political concerns.
Split into simpler sentences: Although he never attained the title of "full professor" during his career, he remained at Halle as a lecturer. Meanwhile he worked at a private medical practice and was devoted to many social and political concerns.