HYGIENE, as a science, traces the causes of disease to which mankind is exposed in every phase of life. Its practical value lies in the preventing of these causes, through the sanitation of our surroundings and the rational care of body and mind. The gradual improvement of public health and the incident saving of vital energies as the result of true hygienic living would easily make this field of knowledge rank among the most potent factors in the development of races. Unfortunately, its greater possibilities are not yet being realized, for want of application, which is, as yet, too much confined to the professions directly concerned with matters of health. The principles of hygiene must be brought home to the people at large, must grow into and form the habits of our daily life. They should, in fact, be applied in every craft and trade, led by the professions, as, for instance, by architects and engineers, upon whom depends largely the healthfulness of our homes, of a multitude of public utilities, and of the commonwealth as a whole. In architecture and engineering, the problems bearing on health should be approached in a spirit independent of mercenary considerations. They ought to be solved strictly on their merits, with a fair perspective towards hygienic quality in all questions of serviceability, ornamental features and structural needs. Such quality is often necessary to the full realization of the aim, and essential to true artistic value as well as to material success. We can not ignore the laws and lessons of nature in building up the city of enduring beauty.
In crowded industrial and commercial centers, the excessive vitiation of the atmosphere has grown to be an important factor bearing on public health. While a systematic supply of pure air to buildings has long been recognized as a necessity, the state of the outer air has not yet received the attention it deserves, and is too often accepted as a matter beyond control. Nevertheless, an inquiry into the sources of its pollution will readily show that much of it might be prevented. That it ought to be prevented is becoming more apparent as its bearing on prevailing diseases is definitely being established. The movement for better ventilation would also gain through a closer study of the causes of impure air. Abundant literature exists on standards of purity, on temperature and humidity, also on the amount of air to be