Annual reports, meeting programs and announcements, meeting proceedings, financial records, member lists, statutes, and correspondence. Topics include: founding of the society, society's centenary, annual meetings of the German Natural Scientists and Doctors, and awarding of prizes. The collection also contains the personal papers of some members, primarily natural scientists, including Heinrich Fl̲ix, Dr. Groeser, C. T. Bruch, Johannes B. Zitz, Dr. R ckeisen, Bronn, M. Alfred Dugis, Pfarrer Schmitt, and Dr. Wittmann. Also meteorological observations of Salomon Anschel, from the observatory in Mainz, 1820-1905, and Munich, 1885-1898. [NOTE - Rheinische Naturforschende Gesellschaft is roughly translated as the Rhenish Natural History Society.]