HYGIENE (Fr. hygiène, from Gr. ὑγιαίνειν, to be healthy), the science of preserving health, its practical aim being to render “growth more perfect, decay less rapid, life more vigorous, death more remote.” The subject is thus a very wide one, embracing all the agencies which affect the physical and mental well-being of man, and it requires acquaintance with such diverse sciences as physics, chemistry, geology, engineering, architecture, meteorology, epidemiology, bacteriology and statistics. On the personal or individual side it involves consideration of the character and quality of food and of water and other beverages; of clothing; of work, exercise and sleep; of personal cleanliness, of special habits, such as the use of tobacco, narcotics, &c.; and of control of sexual and other passions. In its more general and public aspects it must take cognizance of meteorological conditions, roughly included under the term climate; of the site or soil on which dwellings are placed; of the character, materials and arrangement of dwellings, whether regarded individually or in relation to other houses among which they stand; of their heating and ventilation; of the removal of excreta and other effete matters; of medical knowledge relating to the incidence and prevention of disease; and of the disposal of the dead.
These topics will be found treated in such articles as Dietetics, Food, Food-Preservation, Adulteration, Water, Heating, Ventilation, Sewerage, Bacteriology, Housing, Cremation, &c. For legal enactments which concern the sanitary well-being of the community, see Public Health.