Title page of von Weyl’s Manual of Hygiene, Volume 8: Epidemiology and immunity, infectious diseases and disinfection, venereal diseases. 2nd edition, Leipzig 1918

With the outbreak of war, there was a significant increase in premarital and extramarital sexual relations both in the army and the civilian population. The military feared the rapid spread of venereal diseases, and the sexual activity of the troops was therefore of interest to it.