Julius F. Cohnheim, a German-Jewish pathologist who studied with Virchow in Berlin between 1864-68, held chairs of Pathology at Kiel in 1868, Breslau in 1872, and the prestigious University of Leipzig, 1878-84. Cohnheim, who studied "pus" and migration of protective white blood corpuscles (cf. Metchnikoff), also invented the freezing technique of preparing histological thin-sections for tissues or bacteria, and his many technical papers appeared in Virchow's Archiv fur pathologische Anatomie und Physiologie und fur klinische Medizin, Vols. XXII-XLV.

Cohnheim in 1880 published Die Tuberkulose (Leipzig: Edelmann. 2nd edn 1882). As noted by CF: 226 passim, Cohnheim's inoculation experiments, more than any other before Koch, that showed the specific and constant disease nature of tuberculous nodules. A close collaborator, assistant and friend was Karl Weigert (1845-1904), also German-Jewish, whose career movements closely followed those of Cohnheim. Weigert, who specialised in histological staining, especially important with the elusive TB bacillus, discovered vascular TB. Only after Cohnheim's death did Weigert move to a deserved Chair of Pathology & Anatomy at Frankfurt-am-Main (1884). See Ehrlich. As early as 1871 (above) Weigert was staining cocci with carmine, and is often credited as being the first to stain bacteria regularly.

Last modified 3 December 2016