In discussing problems in the control of diphtheria, I do not feel that I am capable of giving any definite answers to the queries that occur when one studies diphtheria, its incidence and its mortality, but I hope that this paper may bring out in its discussion some valuable information. Diphtheria, like all other infectious diseases, brings to the mind of the practitioner four questions:
What is the cause of the disease?
Is there any specific treatment?
Is there any way of rendering immune those persons who are exposed to it?
Is there any way of knowing whether a person exposed to the disease will contract it or not?
CAUSE OF DIPHTHERIA
To all of these questions we can give a definite and precise answer. To the first, the disease is caused by a bacillus first described in 1883-1884 by Klebs and Loeffler. The morphology of this bacillus is well