Rhenish Hesse
Baas was born in Bechtheim, in Rhenish Hesse, and studied medicine at the University of Giessen. He graduated in 1860, and practiced medicine and ophthalmology in various towns of Rhenish Hesse. He undertook research into a number of areas of medicine, including hearing, but became best known for his influential histories of medicine. He died in Worms in 1909.