One of the numerous theories of peptic ulcer is that bacteria are an important etiologic factor. Just how great a part bacteria play is, however, a debated and undetermined question. Bevan1 thinks that hematogenous septic infarcts of the mucosa may have a rôle but are not the common cause. Eusterman,2 on the other hand, states that "the theory that infection is the cause of ulcer is admittedly the only tenable one at this stage of medical progress." Between those two diverse views is the classification of Smithies,3 who divides ulcer from the standpoint of etiology into ten groups, and classifies one third of the total number as bacterial in origin.
Experimental data concerning the infectious theory of ulcer are due almost entirely to the work of Rosenow, who has shown that the intravenous injection of streptococci may be followed by ulcer of the stomach and duodenum; that streptococci are commonly