(_f_) Diphtheria of the throat is eminently an epidemic disease and of a highly contagious and infectious nature. Of late years, the disease occurs in every season of the year, and independently of any epidemic or contagious influence, but it is presumed that the contagion or spores are cultivated in improper sanitary conditions arising from defective sewerage and filthy accumulations. The disease invariably begins with fever, a marked increase of the pulse, increase of the temperature of the skin, and general depression. There is first a difficulty of swallowing, a snuffling voice and stiffness in the neck; the first two signs are due to the swelling and diphtheritic coating of the tonsils, palate and nasal passages, while the last symptom is due to a swelling of the lymphatic glands of the neck which is never absent in genuine diphtheria. If the throat is examined in the early stage, the white membrane is first seen in the tonsils and as the disease progresses it spreads to the palate, the pharynx and the nasal passages. The color of the membrane also changes; after several days it passes into a yellowish-white or grayish-white tint. It has another peculiar feature that distinguishes this membrane from the exudation of ordinary tonsilitis, which the practical eye at once detects; the membrane of diphtheria makes the impression of having eaten into the tonsil or as though it was pressed into the tissue by the finger. And that is really so too, because as a scientific fact it is no membrane at all, but a death or slough of the mucous membrane which may extend down into the tissue beneath the membrane. To treat diphtheria successfully is simple enough but it requires great skill and experience, and I will outline what I consider the proper thing to do and which in my hands saved those lives that were intrusted to my care. The treatment resolves itself into perfect cleanliness or disinfection, stimulating nourishment and internal medication.