In chronic suppuration of the middle ear the success or failure of conservative treatment can not often be predicted from the objective appearances at the first examination. Cases in which we can demonstrate caries, or necrosis or cholesteatoma or involvement of the mastoid cells can, as a rule, not be cured except by operation. But very often the existence of these lesions can only be suspected, not demonstrated.
Any sign, therefore, which enables us to test quickly the efficacy of conservative treatment should be recognized as a valuable guide. I have repeatedly pointed out what important lessons can be learned from the odor of the discharge in the course of treatment.1 It seems to me important enough to revert to this subject in the light of further experience.
With scarcely an exception the discharge of chronic suppuration is characteristically fetid. It has been shown by bacteriologic research that this