Periarteritis nodosa, in adults or children, is a comparatively rare disease of great interest to investigators, whether are are internists, surgeons or pathologists, because of the marked difficulty in correctly diagnosing the condition during life, the bizarre symptomatology and the controversy which exists as to the exact etiology of the disease. The symptom complex may resemble many of the more common and generally well known illnesses, and, in not a few instances, it may so closely simulate an acute surgical abdominal condition that operative procedure may be resorted to mistakenly. Periarteritis nodosa was first described by Kussmaul and Maier in 1866, and has since borne the former investigator's name, particularly in the continental literature. Prior to that, in 1852, Rokitansky reported the finding of innumerable aneurysms in the wall of small arteries over the entire body, except the brain, in a man 23 years old, who had died with the