The longstanding uncertainty or actual confusion regarding the possible causation of Oroya fever and verruga peruviana, diseases of especial interest in the domain of tropical medicine, seem about to be dispelled through the efforts of Noguchi and his collaborators. For many years Oroya fever was regarded as the severe form of an infection of which verruga was merely a milder manifestation. This theory was somewhat challenged in 1913, when a commission from the Harvard School of Tropical Medicine studied both conditions and pointed out that their frequent association in the same persons and their similar geographic distribution did not necessarily indicate that they were caused by the same parasite. Part of the uncertainty has revolved about the rôle of the peculiar intracorpuscular micro-organisms discovered by Barton in 1906 in some cases, and named Bartonella bacilliformis.
Reference has already been made 1 to the fact that Noguchi and Battistini have recently