A Manual of Clinical Allergy: Illustrated

Random samples are : (1) Allergens are environmental agents which do not satisfy the classical definition of antigens. The protein nature of the active agents in pollen is in doubt. An allergen is identified by its reaction on the body. Many substances form, at .the site of injection, conjugate proteins which are antigens. (2) In skin testing the patient should have discontinued all medication against allergy the evening before the day of testing., although ACTH and cortisone do not interfere significantly. (3) The scratch (about 2 mm. in length) or prick test should be carried out before the intracutaneous test. In nearly all the reported deaths this precaution was omitted.