Diphtheria is a common disease, and it is one of the most fatal. As one illustration of many, in five years there were 17,193 cases in New York alone and 7,263 deaths. It is a disease that every physician will be called to treat sooner or later, and being called must act promptly. This is not the place for a long essay upon the different theories of diphtheritic contagion and progress; rather let us enter at once upon the discussion of the practical questions involved in conducting the disease to a favorable issue.
Let me very briefly sketch the manner of invasion according to conclusions which seem most reasonable and are by many accepted:
1. Diphtheria is contagious—or rather portagious, and of parasitic origin.
2. It is most readily implanted upon a mucous membrane denuded of its epithelium.
3. It is probably always local in its incipiency, sometimes becoming rapidly