community must be made, one and all, experts in its knowledge and in its applications.
This last consideration should lead educators to bestow a preëminent importance to a thorough course of instruction in hygiene. It is all well enough for the young to learn more or less about the philosophy of electricity and magnetism, but, as the great majority of them in after-life will make very little, if any, use of this knowledge, its importance practically dwindles to very small proportions. Wholly different is it in the case of sanitary science. Every one can make of it in after-life most important, and ultimately momentous uses, not occasionally, but during every day and hour of life. And, if thus applied, its benefits would transcend those of any other branch of knowledge; it would tend to make man a master of himself, of his pains, deformities, and mortal afflictions.
We have said that the applications of sanitary science must be made mainly by the individual members of society. This is true of the kind of air breathed, of the food and drinks partaken, of the clothing worn, etc., etc. But where human beings are clustered together, their sanitary relations are so intimate that it becomes absolutely necessary for the general good to define and regulate some sanitary matters by law, which each member of a community cannot, as an individual, regulate for himself. It is not possible, for example, for one in a densely-populated place, to enforce regulations for a supply of wholesome water, for carrying off to a safe distance all the refuse and noxious matters of a great city, or to protect himself from the presence of persons suffering from infectious diseases. It is here plainly the duty of the State to exercise supervision for the general good, and to protect all, as far as may be possible, against evils which a few persons may fight against in vain. There is absolutely no difference, except in the matter of will, between the danger of allowing a person who has a mania for putting poison into the drinking-water of a city, by which many perish, and one who puts the poison of small-pox into the air of a city by which hundreds are slain. In the former case, even if it were the work of an idiot, or of an irresponsible person, and if he were known to be travelling over the country, liable at any moment to enter a city, would not the officers of the law be considered exceedingly derelict in duty if they did not carefully guard against his entrance? And, if such a class of persons were in a city infecting others with their mania, would not all applaud the law and the efforts of its officers in securely confining them where they could do no harm, taking from them the means by which they injured and destroyed the lives of others? This is precisely what ought to be done with every one in a densely-populated place laboring under an infectious or contagious disease. When out of a city, such dangerously-affected persons should be watchfully excluded until cured of their disorder; and, when in, a cordon should be placed around them, so that the com-
