Jan Fryderyk Knolle's forgotten dissertation on osseous syphilis, 1763

In 1763 Jan Fryderyk Knolle, a Polish physician, wrote his doctoral thesis on osseous syphilis, De Ossium Carie Venerea, at the University of Leipzig, Saxony (now East Germany). Knolle described the pathology, clinical picture, and treatment of syphilis of the bones and emphasized the severity and destructiveness of bony lesions, which could occur even in the early stage of the disease. An interesting and detailed drawing showing osteomyelitis of the femur, which appears to be of syphilitic origin, was included in Knolle's dissertation. This illustration is an example of 18th century syphilologic iconography. A comparison of the clinical picture of syphilis as described by Knolle with that of the present day suggests that syphilis has become a milder disease.