Working under William H. Weston at Harvard, Raper studied an organism he had collected in the Great Craggy Mountains of North Carolina during the summer vacation, and which he formally described as Dictyostelium discoideum in 1935.
[1] After Harvard, Raper re-joined the USDA, at a new laboratory set up in Peoria, Illinois, working on ways of improving yields of dairy derivatives.
[1] The English mycologists Howard Florey and Norman Heatley had been isolating penicillin at the University of Oxford, but were looked for ways to improve the quantities produced.
Through collaborations with other groups across the United States, more efficient strains were identified – the best coming from a moldy cantaloupe brought in by a Peoria housewife in 1943 – and enough penicillin was produced to be made available to the Allied troops in time for the D-Day landings.
Notable students who continued his work on dictyostelid cellular slime molds include Theo Konijn[2] and James Cavender.