The physical education of children is a very simple matter, too simple to be much attended to without great perseverance and resolution on the part of those who care for the children. It consists, as we all know, in good air, simple diet, sufficient exercise, and judicious clothing. The first requisite is the most important, and by far the most frequently neglected. This neglect is not so unreasonable as it seems. It arises from pure ignorance. If the mass of mankind knew what scientific men know about the functions of the air, they would be as careful in getting a good supply of it as of their other food. All the people that ever were supposed to die of poison in the middle ages, and that means nearly everybody whose death was worth speculating about, are not so many as those who die poisoned by bad air in the course of any given year. Even a slightly noxious thing, which is constant, affecting us every moment of the day, must have considerable influence; but the air we breathe is not a thing that slightly affects us, but one of the most important elements of life. Moreover, children are the most affected by impurity of air. We need not weary ourselves with much statistics to ascertain this. One or two broad facts will assure us of it. In Nottingham there is a district called Byron Ward, “the densest and worst-conditioned quarter of the town.” A table has been made by Mr. William Hawksley of the mortality of equal populations in different parts of the town: “On comparing the diagram No. 1, relating to Park Ward, with the diagram No. 7, relating to Byron Ward, it will be seen that the heavier pressure of the causes of mortality occasions in the latter district such an undue destruction of early life, that towards 100 deaths, however occurring, Byron Ward contributes fifty per cent. more of children under five years of age than the Park Ward, for the former sends sixty children to an early grave, while the latter sends only forty.” {116a} Mr. Hawksley, the former witness alluded to, goes on to say—