The control of diphtheria in any institution for the care of children might center itself around a careful consideration of these points :1. The chronicity of illnesses such as heart disease, orthopedic conditions, choreas, empyemas and burns, which prolong the period of hospitalization and increase the possibilities for contact.2. The inadvertent admittance of patients with diphtheria, perhaps indistinguishable at times or even masked by the clinical pictures of colds in the head, follicular tonsillitis or laryngitis.3. The carriers of diphtheria bacilli, consisting of those recognized by the hospital laboratory and that unrecognized circulating group invariably present among the patients and personnel of such institutions.4. The lack of alertness among the members of the active unit of the From the Children's Memorial Hospital and the Otho S. A. Sprague Memorial Institute Laboratory.