Photography and modern medicine were born about the same time. The presentation by Louis-Jacques-Mandé Daguerre of the daguerreotype (1839), the first practical form of photography, came only seven years before the first public demonstration (at Harvard) of general anesthesia. The discovery of antisepsis by Lord Joseph Lister, which made safe surgery possible, came only decades later, in 1867. Thus, early photographers, many of whom were also physicians, visually documented medical practices that were soon to be superseded by these breakthroughs. Photography became not only a device to record and teach, but, with the discovery in 1895 of the X-ray by physicist Wilhelm Conrad Röntgen, a major diagnostic tool as well.