*Period of Invasion (Initial Stage).*--At the outbreak of the initial symptoms of smallpox a correct diagnosis is rarely made, owing to the fact that headache, lumbar pain, chills, fever, and nausea are not sufficiently pathognomonic to always suggest the true nature of the disease. In those cases, however, where it is known that the patient has been exposed to infection and an attack of variola is consequently anticipated, the diagnosis is comparatively easy. In such a case the patient should be put to bed, or at least confined in a large, airy room, from which all draperies and superfluous articles, capable of absorbing infectious germs, should be at once removed. The temperature of the room should be kept as low as possible in summer and should not exceed 60° to 65° F. in winter. An extra bed or couch should be provided, to which the patient can make a convenient and agreeable change later in the course of the disease, especially if it proves to be of a severe type. At the outset the bowels should be freely opened by a dose of calomel and soda, followed in the morning by a saline purgative; and since constipation is apt to persist in most cases throughout the course of the disease, it is advisable to administer a little cold citrate of magnesia or some other agreeable laxative from day to day. A warm bath should be taken and the skin from head to foot thoroughly cleansed by vigorous soap friction and the application of an antiseptic lotion. If the disease proves mild, a daily bath can be taken; or when this does not seem advisable, the daily sponging of the whole body with cool water will usually lessen the fever and add greatly to the comfort of the sufferer. If the patient happens to belong to the class of the unvaccinated, or has not been vaccinated for many years, and there exists consequently the prospect of a severe attack, the hair and beard should be closely clipped. In most cases, however, this procedure can be left until the eruption has appeared, and if this is moderate in amount, the cutting of the hair, especially in the case of young girls and women, may not be necessary. The diet, which throughout the course of smallpox is a matter of the greatest importance, should be light and nutritious during this stage, consisting mainly of milk, broth, or gruel.