A hitherto undescriptionbed complication of INAH therapy is reported. Twenty per cent of 59 cases receiving the drug for pulmonary tuberculosis presented a clinical picture resembling peripheral neuritis. Representative cases are descriptionbed and tentative explanations offered.
1. Attention is directed to the normality of paranasal sinus variation and the need for its regular consideration. 2. The various types of ompartmentation of the maxillary field are descriptionbed. 3. Clinical observations suggesting the presence of compartmentation in general, and true duplicate antrum in particular, are reported and reasons for same advanced. 4. Methods of diagnosis are outlined and attention drawn to the absolute importance of confirmatory contrast radiography. 5. Important details for the achievement of radiographic contrast proof are presented and the best agents to this end suggested. 6. An illustrative and proven clinical case is reported.