"One great advance in connection with typhoid fever has been made of late years, and of this I am come specially to ask you to take advantage. An attack of an infectious disease so alters the body that it is no longer susceptible to another attack of the same disease; once a person has had scarlet fever, smallpox, or chicken pox, he is not likely to have a second attack. He is immune. When bacilli make a successful entry into our bodies, they overcome the forces that naturally protect the system, and grow; but the body puts up a strong fight, all sorts of anti-bodies are formed in the blood, and if recovery takes place, the patient is safe for a few years at least against that disease. "It was an Englishman, Jenner, who, in 1798, found that it was possible to produce this immunity by giving a person a mild attack of the disease, or of one very much like it. Against smallpox all of you have been vaccinated--a harmless, safe, and effective measure. Let me give you a war illustration. General Wood of the United States Army told me that, when he was at Santiago, reports came that in villages not far distant smallpox was raging, and the people were without help of any kind. He called for volunteers, all men who showed scars of satisfactory vaccination. Groups of these soldiers went into the villages, took care of the smallpox patients, cleaned up the houses, stayed there until the epidemic was over, and not one of them took the disease. Had not those men been vaccinated, at least 99 per cent of them would have taken smallpox. "Now what I wish to ask you is to take advantage of the knowledge that the human body can be protected by vaccination against typhoid. Discovered through the researches of Sir Almroth Wright, this measure has been introduced successfully into our own regular army, into the armies of France, the United States, Japan, and Germany. I told you a few minutes ago about the great number of cases of typhoid fever in the volunteer troops in America during the Spanish-American War. That resulted largely from the wide prevalence of the disease in country districts, so that the camps became infected; and we did not then know the importance of the fly as a carrier. But in the regular army in the United States, where inoculation has been practiced now for several years, the number of cases has fallen from 3.53 per thousand men to practically nil. In a strength of 90,646 there were, in 1913, only three cases of typhoid fever. In France the typhoid rate among the unvaccinated was 168.44 per thousand, and among the vaccinated .18 per thousand. In India, where the disease has been very prevalent, the success of the measure has been remarkable.