In arranging the many subheadings and topics which have developed in the study of allergy, one finds that some of these are concerned with the basic cause of trouble, others with the development of sensitiveness, others with the mechanisms by which symptoms result, others with the variety of symptoms, and, finally, still others with those changes which have nothing to do with the cause but represent the result or the effect of the primary disturbance.
Last winter I1 prepared an informal talk along these lines, and the summary was published later in a small bulletin. The chart presented at that time has proved to be a useful arrangement of the various topics and so is presented again here, with some modification. First of all, this chart separates allergy as a study in immunology sharply from asthma, a study in physiology. It is true that often the two go together,