HEALTH (from the same root as heal, hale, whole), the state of the body or mind opposed to disease (q. v.) and characterized by the integrity or soundness (Lat. sanux) of all the parts and functions which constitute a living being. In the more restricted and ordinary sense, health is understood as referring chiefly to the body, and as indi cating that perfect and harmonious play of alI the functions which permits a man to be all that his Creator intended. Even in this sense, however, it may readily be admitted that absolute bodily health is one of the rarest of endowments; in common language, accordingly, the term is accepted with an indefinite limitation, to indicate a state consistent with a life reaching its ordinary physiological limit without any mani fest and considerable departure from the ideal standard.
As the absolute and extreme duration of human life is uncertain, it is usual to regard as a healthy state of the system that in which a moderate degree of activity, without pain or inconvenience, is maintained beyond the limit of threescore-years-and ten, as indicated by the Psalmist. In point of fact, however, no considerable corn munity of human beings can be said even to approach this term of life on an average of cases. Even where the adults are more than commonly long-lived, there is always a considerable mortality at very early ages, which tends to reduce the statistical vitality, so to speak, of the whole community below the point which would be indicated by an average of 70 years for the population at large. Thus, in a population dying at the rate of only 15 in 1000 annually (the lowest permanent rate in the returns of the regis trar-general for England), the average age at death of the community, supposing the population to be absolutely free from change, would be only 66.6; and in the case of a
death-rate of 20 in 1000, the average age at death would be 50; while a death-rate of 25 in 1000 (the actual death-rate of London, the healthiest of the great European capitals) would correspond to an average age at death of not more than 40. Setting aside fluc tuations of population, which always exercise a certain influence on the result of such calculations, it may be said that the average duration of life in England and Wales is about 45 years, and in Scotland somewhat less than 50 years; and to the extent expressed by these figures, the health of these. two great countries falls short of the ideal standard. This subject will be more fully considered under the article VITAL STATISTICS, in which a view will be given of the phenomena of the death-rate, as affecting the calculation of premature mortality, with a view to the removal of its causes in great communities. This department of science has assumed great importance of late years, in consequence of the efforts that have been made to improve the sani tary condition of our great towns and country districts by improved drainage and sewerage, a regulated supply of pure water, and the inspection, in certain circum stances, of lodging-houses, and even of private dwellings, so as to prevent overcrowding, and the other manifest causes of the spread of epidemic disease. These, and other great practical reforms, constitute the object of what has been called the " Public Health " movement in this country, some notice of the-history, progress, and practical results of which- is given the head of 8ANITAtY SCIENCE.