While we have come to consider diphtheria as a manageable disease, it is still a troublesome problem to the sanitarian as well as serious and inconvenient to the patient. Antitoxin is a very expensive remedy, it is not always immediately available, particularly in country districts, and we can hardly consider it an infallible remedy. A still more serious embarrassment is the sometimes protean character of the disease which allows it to go unrecognized and untreated until serious consequences are inevitable. Many physicians have had to make retrospective diagnoses of diphtheria to account for formidable paralyses, etc., in their patients, while the control and prevention of the disorder is greatly hindered by this fact of its almost impossible diagnosis, in so many cases, by the ordinary clinical methods. The subject of latent diphtheria, treated of in this issue of The Journal by Dr. M. Solis-Cohen, is, therefore, a very important one.