Recent publications (I, 2) have described the influence of the "wax" of the human tubercle bacillus in causing guinea pigs to respond with the delayed form of hypersensitivity to tuberculoprotein. In all essential features the hypersensitive state established by the use of these two bacteria-free components of the bacillus reproduced the allergy of infection, including cutaneous and systemic responsiveness to old tuberculin, a modified (non-necrotizing) Koch reactivity to the intracutancous injection of bacilli, and reactivity of explanted tissue to the presence of tuberculin.A natural sequence to these observations has been the question of the influence of this lipoidal fraction in altering the type of hypersensitivity to other antigenic substances unrelated to the tubercle bacillus. Since tuberculoprotcin alone performs immunologically like any other antigenic protein, inducing humoral antibody and anaphylactic sensitivity, and since these activities are extended by the addition of the wax to include induction of delayed allergy, it is reasonable to suppose that this function of the wax might reveal itself as well with any antigen. This view has bccn implemented with evidence in the case of picryl chloride (3).Over twenty years ago Dicnes and his coworkers (4-6) showed that the injection of egg white into tuberculous guinea pigs, or into animals receiving injections of killcd tubercle bacilli, resulted in a type of reactivity to intracutaneous injection with this antigen which differed considerably from that ordinarily seen in animals sensitized with egg white. In the tuberculous animals the dermal reactions to egg white persisted for 48 hours, and were often necrotic. In contrast, skin tests in sensitized non-tuberculous animals resulted in the usual edematous reactions of the Arthus type which reached their peak within a few hours and vanished or waned considerably within 24 hours. The former reaction resembles the tuberculin type of hypersensitive response; the * This work has been