In the May 28, 1938, Lancet, Whitby1 reported that sulfapyridine (2 [para aminobenzene sulfamide] pyridine, "M. & B. 693," "Dagenan") was an efficient chemotherapeutic agent in the treatment of experimental hemolytic streptococcic, meningococcic and pneumococcic infections in mice. The therapeutic activity of this compound seemed to be especially noteworthy in experimental infections produced by types I, II, III, V, VII and VIII pneumococci. Subsequently Whitby2 stated without giving experimental detail that sulfapyridine was also an active chemotherapeutic agent in the treatment of staphylococcic infections in mice. My associates and I3 have, in the main, confirmed Whitby's experimental observations regarding the therapeutic efficiency of sulfapyridine in experimental hemolytic streptococcic, pneumococcic, meningococcic and staphylococcic infections and in addition have found that this compound is also effective in experimental Friedländer's bacillus and Clostridium welchii infections in mice. Our experience would lead us to believe that the drug is about as