How shocking conditions are, in view of the sanitary and medical knowledge we now possess, we are not apt to realize. It is estimated that of the three million or so who are seriously ill in this country on any average day, more than half might have been kept well by the enforcement of proper precautions; that of the 1,500,000 deaths that occur annually in the United States, nearly half could have been postponed. Tuberculosis, for example, is not a highly contagious or rapid disease; it is absolutely preventable by measures now understood, and almost always curable in its earliest stages. Yet half a million people in our country are suffering from it, and about 130,000 die of it annually. Typhoid, which could readily be as nearly eradicated as smallpox has been, claims some 30,000 victims annually. It has been estimated by various statisticians that the nation could save a billion dollars a year through postponing deaths, and at least half as much again by preventing illness that does not result fatally. Tuberculosis alone is said to cost the country half a billion annually, typhoid over three hundred million, and so on. The cost in suffering, broken lives, and broken hearts is beyond computation. There are many different ways in which the campaign for public health can be simultaneously waged: (1) The enforcement of quarantine laws, vaccination, and fumigation, should be much stricter than it is in many parts of the nation. By such means the cholera, bubonic plague, and other terrible diseases have been practically kept out of the country, and smallpox has become, from one of the most dreaded scourges, an almost negligible peril. Experience shows strikingly the advantage of isolating patients suffering from contagious diseases; here at least the State, in the interest of the community as a whole, must sternly limit individual liberty. And it looks as if we were at the threshold of an era of "vaccination" for other diseases besides smallpox; typhoid is now absolutely preventable by that means, and the number of diseases amenable to prevention or mitigation by similar methods is yearly increasing. In some or all of these cases there is a slight risk to the patient, in view of which compulsory "vaccination" is in some quarters strenuously opposed. Leaving the discussion of the principle here involved to chapter XXVIII, we may confidently say, at least, that voluntary inoculation against diseases is an increasingly valuable safeguard not only for the individual in question but for the whole community.