been found as the morbid agent in any other similar affection, or in a spontaneous disease among lower animals; nor is there any existing evidence to support the idea that true diphtheria may be conveyed from sick animals to human beings.
The diphtheria bacillus may be found in the air passages, especially the nose, of healthy persons, in whom it has produced no disturbance whatever, nor does it cause any indication of sickness until it has settled down for good. Lesions of the mucous membrane of the nose or throat, small eruptions in the air passages, chronically enlarged tonsils, and especially catarrhal changes consequent upon cold, damp weather, favor the development of the bacillus. If these membranes are normal, the bacillus finds insufficient material in which to multiply, and the poisonous products that it forms are thrown out with the mucus ordinarily produced; but if there is any lesion or disorder of the membranes, then these poisonous products act at first locally and cause such disturbances of the usual processes of the affected region that the bacilli multiply vigorously and form such quantities of their poison that it is absorbed into the system and the disease follows.
From the moment the bacilli are found on the membranes the person should be regarded as infected, and the term diphtheria should be reserved exclusively for those affections in which this particular bacillus is found. Not infrequently cases are met with that present the physical features of diphtheria, but a bacteriological examination will show that the condition is due to other organisms, such as pneumococci, streptococci, and staphylococci. Indeed, in 1887 Loeffler announced that, in addition to the organism identified with his name and Klebs's, there occurred in diphtheritic membranes another organism resembling it in many essential respects, but differing from it in its disease-producing power, and to this organism he gave the name of pseudo-diphtheria bacillus; these bacilli are shorter and more uniform in size than the typical Klebs-Loeffler bacillus.
The importance of distinguishing between these forms of throat inflammations is apparent when it is recalled that the specific character of the disease not only determines the necessity of isolating the affected person but also the method of treatment that should be followed. New York was the first city in which a municipality endeavored to make that distinction, and what is now known as the "New York plan" was inaugurated by Prof. Hermann M. Biggs, and his associate, Dr. William Hallock Park, of the Board of Health. In New York, as in most cities, physicians are required to report the cases of diphtheria they are called upon to treat; if the environment of the affected person renders it desirable to transfer the individual to a hospital for contagious diseases, it is a matter of importance to decide that