Johannes Orth

ORTH, Johannes (1847–1923), a prominent German pathologist. He graduated from the medical faculty in Bonn in 1871, served for two years as an assistant in the pathological institute of the University of Bonn under Professor Rindfleisch, where he obtained his privatdocent qualification in 1872. In 1873, he was invited as an assistant to Virchow at the pathological institute of the University of Berlin. In 1878, he was elected professor in Göttingen, where he held the chair for 24 years. In 1902, after Virchow's death, he moved to the latter's chair in Berlin and headed the Virchow Pathological Institute at the Charité hospital until 1917, when he retired due to length of service. Of Orth's 225 scientific papers, his research on tuberculosis holds the greatest significance; in it, he addresses the connection between scrofula and tuberculosis, elucidates the relationship of bovine perlsucht to tuberculosis, enters into a discussion with Robert Koch regarding the significance of the bovine tuberculosis bacillus for the pathogenesis of human tuberculosis—with Koch denying this significance—and emerges victorious from this discussion; he works out in detail the pathological anatomy of pulmonary tuberculosis, establishing the morphological distinction and at the same time the etiological unity of pneumonic and granulation processes in pulmonary consumption; in his endeavor to decipher the essence of this distinction, he was the first to express the opinion regarding the significance of constitution and disposition for the morphological expression of the pathological process. A large number of Orth's works are devoted to malignant neoplasms, especially cancer, and in particular the significance of metaplasia in so-called precancerous states. Of no small importance are Orth's studies on the pathological anatomy and etiology of erysipelas, diphtheria, postpartum sepsis, the question of fibrinous inflammation, and exudative cells in meningitis. In addition, Orth worked extensively on the subject of alcoholism and its role in tuberculosis and other diseases. Orth's name is also known in histological technique as one of the first pathologists to draw attention to the fixing properties of formaldehyde, as well as for proposing a fixing fluid (10 parts formalin + 90 parts Müller's fluid), which became known as Orth's fluid, and a lithium carmine solution, named Orth's carmine. Orth's textbook Pathologisch-anatomische Diagnostik (6th ed., Berlin, 1917) went through 6 editions and was translated into many languages, including Russian (2nd Russian ed., St. Petersburg, 1890). Professors Aschoff, Benda, Herxheimer, and many others emerged from Orth's school. Orth was an honorary member of numerous scientific societies and academies of various countries. During his tenure at the chair in Berlin, he was the permanent chairman (in his final years, honorary chairman) of the Berlin Medical Society.