True allergy is a hypersensitivity of tissue cells to allergens. The cells of practically every tissue of the body may acquire a hypersensitivity. This may come about through either systemic or local absorption of the allergen in a person in the proper biochemical or physiologic state. Likewise, in some persons nearly every tissue may develop an immunity. Most persons who become allergic inherit a tendency. Then infection, shock or emotional strain may precipitate the allergic state when the subject is exposed to allergens in sufficient quantities. The various tissues of the eyes are no exception to the susceptibility to allergic manifestations. No effort will be made to review the literature on allergies in ophthalmology, as that has recently been well done by Appelbaum.1 To understand better the allergies of the eyes it is necessary to have a good conception of allergies in general. From over 50 per cent of