One of the fundamental principles of society is that each individual must, in his methods of living, conduct himself with a due regard for the rights, comfort, and health of others in the same society. A single man or a single family living alone on a desert island requires no restrictions of conduct, since there are no fellow-beings on whom his violations of good conduct might react. The inhabitants of small villages with small families on large lots are but little concerned with laws governing social intercourse, since, at best, the amount of that intercourse is inconsiderable. But, as population becomes greater, as congestion increases, and as civilization and its requirements develop, the need for law governing the interrelations of individuals becomes imperative. Such laws deal with the moral life under many phases, and the courts exist for the enforcement of such laws as the people themselves, through their legislatures, demand for their own self-protection. One of the primitive laws found necessary, even among uncivilized people, is that against theft, and, whether committed in the barbarous tribes of Africa or on the frontier plains of the West, the act is recognized as being contrary to the greatest good of the community, and, if detected, is severely punished. As civilization advances, the code of laws found necessary becomes more and more complex, and, although use has made obedience to such laws almost second nature, it is hardly possible to-day to escape the immediate restraint of such laws for more than a moment at a time throughout any period of twenty-four hours. _Principle of laws of hygiene._ It is particularly the laws which pertain to health and hygiene which we shall consider in this chapter. The principle on which laws relating to hygiene are passed is that while nominally a person is always free to do with his own whatever he may choose, yet as a member of a community he must choose to do only that which shall not injure or affect the health or comfort of his neighbors. This principle was not at first invoked to prevent violations of laws of health, but rather to prevent the inconvenience which might come to a neighbor or to the public at large by some unreasonable though apparently legitimate use of individual property. As an example we may mention the law of New York State requiring each owner of property in the country to cut grass, weeds, and brush along the highway twice each year. Although this interferes with the right of the owner to have the land which belongs to him left as he chooses, it is legal because of the greater convenience and comfort it contributes to the larger number of persons traveling along the highway.