CARRIÓN'S disease is caused by Bartonella bacilliformis, a polymorphous organism classified as a bacterium in 1927 by Noguchi,1transmitted by sandflies of the genus Phlebotomus. The disease is limited geographically to certain areas of the Andean regions in Peru, Colombia and Ecuador. The disease is extremely polymorphic in symptoms. The confusion existing in the literature arose in part from reports prior to the discovery of B. bacilliformis, when intercurrent infections were not recognized and many symptoms were erroneously assigned to Carrión's disease. The present report is based on a study made on several hundred cases in Lima, Peru, during the period 1938 to 1943. HISTORY AND NOMENCLATURE Archeologic findings indicate that the disease was known in Peru in the pre-Incaic era. Surprisingly accurate representations of the cutaneous nodules, or verrugas, are found in the Peruvian ceramic pots calledhuacos, especially in the Chimu civilization.2The first medical publication