For OR MANY years bacterial endocarditis has seemed to evoke widespread interest among clinicians. Of all the protracted febrile illnesses it has been one of the most challenging as an exercise in diagnostic acumen. The reasons for this have been several. First, the site of infection is impalpable and cannot be visualized even with the most modern diagnostic techniques. Second, the cardinal signs—fever, heart murmur, and emboli—may often be caused by other diseases, or they may be absent in endocarditis. Finally, the nature of embolization is such that lesions may be produced in any organ and readily simulate other disorders. In spite of such widespread clinical interest, however, the disease is sufficiently uncommon and sufficiently complex that it may readily be missed for long periods. For example, in three recently reported series1-3 the average duration of symptoms prior to initiation of definitive therapy ranged from 2.2 to 5 months.