The disagreeable symptoms observed in patients suffering from sensitiveness to pollen vary with the pollen content of the air. In fact, in many districts, symptoms appear at the beginning of the pollen season and disappear completely with the termination of the season. If a patient can be moved from a given pollen district to one in which the air is nearly free of pollen (as can be accomplished by an ocean voyage), symptoms usually disappear only to return again on exposure to air that is rich in pollen. This principle in treatment (avoidance of pollen) has been used arbitrarily for centuries perhaps by physicians who have advised change in climate for the cure of asthma. In a certain proportion of patients, symptoms are less marked if a patient can remain in a pollen-free atmosphere part of the day. This method of treatment has been studied especially by Cohen and others