[1] By way of a request from the Jaluit Gesellschaft, he traveled to Nauru in an effort to fight a disease affecting coconuts.
[2] In 1908–10 he participated in the Südsee-Expedition to Micronesia under the directorship of Georg Thilenius, head of the Ethnological Museum in Hamburg.
In the South Seas, he conducted ethnographic research on Nauru, Ponape and other islands.
[1] After returning to Germany, he was named director of the Oceania department at the Ethnological Museum in Hamburg.
In 1922 he was appointed professor of anthropology at the University of Hamburg, where he also gave classes on the traditional customs and folklore of rural Europe.