Robert KOCH (1843-1910) German physician, discoverer of the tubercle bacillus. L.A.S., Berlin March 7, 1886 to a colleague; 1 page in-8; in German (photo postcard attached). According to his information, the most suitable for microphotographic and projection purposes is the contact lamp ("Contact-Lampe") of Siemens and Halske, based on the Hefner-Alteneck system. He bought this lamp and is very happy with it.