Sarasins explored different groups and tribes in Ceylon and Celebes, which they saw as varieties of men created differently by evolution and at different stages of biological and cultural development. In Ceylon they visited and studied intensively a tribe called Weddas which they considered to be the oldest and original population of Ceylon, living mostly as hunters in the mountains and inner parts of Ceylon. They compared them to other groups in Ceylon, the Tamils and the Sinhalese. Later the Sarasins found a group of people in Celebes, in their opinion similar to the Weddas, the Toala and Toraja. For their research the Sarasins crossed Celebes seven times on different routes. Since the island was at this time only loosely controlled by the colonial administration of the Netherlands, they had to travel through mostly unknown areas of the nearly independent kingdoms of Luwu, Sidenreng and Bone. These kingdoms belonged to the cultural groups named Bugis or Makassars. Hierarchically structured, each with a king on top, elected by noble families, and an associated parliament of lower nobles, they competed for power and resources, like slaves, to produce coffee and spices, which they sold to the world-market. Lower groups of the Bugis and tribes from the inner mountainous parts of Celebes, like the Toraja, lived in a kind of slavery. According to the scientist B.C.Schär, the research of the Sarasin later led to the inclusion of these areas into the Dutch colonial imperium. When Fritz Sarasin travelled 1910 - 1911 to the islands of New Caledonia in the South Pacific, he met there with another ethnologist from Basel Felix Speiser, who at this time did research on the New Hebrides. Paul and Fritz could finance their research from their own, mostly inherited, wealth. From 1906-1912, Paul Sarasin was President of the commission for the Ethnological Museum of Basel. Paul and Fritz donated their rich collections to the Ethnological Museum. Alone from Celebes they brought back to Basel 1000 animals and plants, as well as 680 ethnographic objects and 600 photos. Along with Hermann Fischer-Sigwart, Jakob Heierli, Albert Heim, Hans Schardt, Carl Schroter, Ernest Wiczek, and Friedrich Zschokke, they were the founders of the Schweizerische Naturschutzkommission (the Swiss Nature Conservation Commission). At the age of 62, Paul married in 1918 Anna Maria Hohenester and got two children with her. Taxa named in his honor Paul and Fritz Sarasin are commemorated in the scientific