Ploetz was born in
Swinemünde,
Germany (now
Świnoujście,
Poland). He grew up and attended school in
Breslau (now
Wrocław). He was a friend of Carl Hauptmann, brother of the famous author
Gerhart Hauptmann. In 1879, he founded a secret racial youth society. In Gerhart Hauptmann's drama
Vor Sonnenaufgang ("Before Sunrise"), which was first performed on 20 October 1889 in
Berlin, the key figure of the journalist Loth was based on Ploetz. After he had finished school, Ploetz at first studied
political economy in
Breslau, where he joined the "Freie Wissenschaftliche Vereinigung" (Free Scientific Union). Among his friends were his brother, his former school friend Ferdinand Simon (later son-in-law of
August Bebel), the brothers Carl and Gerhart Hauptmann, Heinrich Laux and
Charles Proteus Steinmetz. The circle enthusiastically read the works of
Ernst Haeckel and
Charles Darwin. Carl Hauptmann was a student of Haeckel, and Gerhart Hauptmann and Ploetz attended some of Haeckel's lectures. The group expanded and developed a plan of founding a colony in one of the Pacific states and established itself as the "Pacific Association". It planned a "community on friendly, socialist and maybe also pan-Germanic basis". In consequence of the prosecution of socialistically-minded persons in application of
Otto von Bismarck's antisocialist laws (1878–1890), Ploetz in 1883 fled to
Zürich, where he continued to study political economy with
Julius Platter (1844–1923). In his memoirs, Ploetz stated as an important reason for his choice of Zürich that in his studies in Breslau, socialist theories had been only incidentally mentioned. After living for a half a year in the
United States, Ploetz returned to Zürich and began to study medicine. In 1886, he fell in love with a fellow student,
Agnes Bluhm, but he was involved with Pauline Rüdin; the last two decided to get married early in 1887. Ploetz was also seeing an American, Mary Sherwood, who was studying hypnotism. ==Career==