Periarteritis nodosa is an unusual and relatively uncommon vascular disease. As late as the middle of 1933 only 195 verified cases were to be found in the medical literature.1Seventy-seven of these had been reported after 1926. Kussmaul and Maier2in 1866 made the first anatomic description of the disease. In 1878 Meyer3described a triad of symptoms characteristic of periarteritis nodosa: first, chlorotic marasmus; second, polymyositis and polyneuritis, and, third, gastro-intestinal symptoms. Brinkmann4and Christeller5later emphasized nephritis as a fourth cardinal symptom. Arkin6in 1930 described in detail the pathologic lesions. The case reported here presented a clinical picture simulating an acute surgical condition of the kidney so closely that nephrectomy was performed. REPORT OF CASE First Entry.— T. M., a married man, aged 29, a tilesetter, admitted to the University of California Hospital in the medical teaching service, March 30, 1931,