Reports from various theaters of operation indicate that external otitis is a problem of considerable importance as a cause of lost man hours of work in certain tropical and subtropical regions. There have been repeated requests for a study of this disease with a view toward devising a simple and expedient treatment which can be used under field conditions. It is generally accepted that external otitis may be caused by bacteria, by fungi or by a mixture of bacteria and fungi. Of the varieties of fungi which have been isolated from the external ear,1 species of Aspergillus appear to be the most frequently encountered in cases of external otitis.2 Eleven species of the genus are listed by Dodge 3 as having been isolated from the aural canal. Penicillium and the closely related Scopulariopsis occur occasionally and are of relatively little importance.4 The genus Mucor is represented by three species from the ear.5 Monilia is also reported to be involved in otomycotic infections.6 A large number of other varieties have been reported as isolated from the ear but seem to be of minor importance in com¬ parison with those just enumerated.The agents most frequently used in the treat¬ ment of external otitic infections at present are local applications of 95 per cent alcohol alone or of this combined with boric acid, 2 per cent salicylic acid in 70 per cent alcohol, 1 per cent thymol in alcohol, metacresyl acetate (cresatin), and potassium iodide or sulfonamide compounds by mouth. The clinical effectiveness of cresatin was emphasized by Gill ' and has been confirmed by other workers.8 The combination of cresatin with thymol has been employed with good re¬ sults by some investigators.9 McBurney and Searcy10 and Schamberg and KolmerX1 have studied a considerable number of substances for their fungicidal and germicidal effectiveness.Both in vitro and in the treatment of otomycosis,McBurney and Searcy found that 2 per cent thymol in alcohol was the most effective agent, though only slightly superior to cresatin. Alco¬ hol, which has been widely used, was found to have little fungicidal action by these workers. A recent report12 deals with the treatment of 64 patients for external otitis, 38 of whom were treated by the local application of sulfanilamide, sulfathiazole or a mixture of these with zinc peroxide. The local insufflation of a mixture of powdered sulfonamide compounds in cases of acute external otitis resulted in a more rapid subsidence of pain and a marked decrease in the time required to effect a complete cure as com¬ pared with other acceptable procedures. Because of the relative difficulty of the application of cresatin and thymol by those who are not trained otologists, and since a supply of sulfon¬ amide compounds is easily available in all theaters of operation, it was felt that the encour¬ aging clinical results with the sulfonamide com¬ pounds warranted further study. The present
