In a previous report1several groups of cases were described and classified under the general designation of nonbacterial thrombotic endocarditis. This form of endocarditis is characterized by thrombotic vegetations, often of unusual size and appearance, with a minimum of reaction in the valve itself. It differs from the variety due to acute rheumatic infection and from the type described by Libman and Sacks as "atypical verrucous endocarditis."2Among the several subdivisions of nonbacterial thrombotic endocarditis, two appear to have certain clinical and pathologic features in common. One of these subdivisions (reported on elsewhere3) was represented by a group of three cases characterized by acute (thrombocytopenic) purpura haemorrhagica, nonbacterial thrombotic endocarditis and vascular lesions which were widespread in one case and considerably milder in the other two cases. The present communication is a detailed account of another group of cases in which prolonged fever, arthritis, inflammation of the