IN THE temperate zones otologic practice can be divided generally into two distinct seasonal phases. One is the summer phase, during which conditions are essentially the same both indoors and out as regards temperature and humidity. During the second, or winter, phase people live in different environments, the dry, warm indoors and the variable, cold outdoors. During this phase the human economy is subject to great fluctuations of temperature and humidity over relatively short periods. As a result, people have fall, winter and spring colds, with the ensuing complications, not the least of which are otogenic infections, such as otitis media and mastoiditis. During the summer phase otologists see relatively few infections of this type but a greatly increased number of external otogenic infections. In addition, they frequently encounter exacerbations of chronic otogenic infections, which have been artificially activated by swimming, excessive sweating and bathing, with consequent pathologic aural changes.