There is a widespread and growing belief in this country that the problems of ventilation are in need of exhaustive investigation. Some of the aspects of this subject, and particularly their bearing on hospital ventilation, have been discussed in detail in a series of papers in The Journal.1 Physiologic research has brought about a new attitude in regard to what constitutes "foul air." The chemical composition of the atmosphere, its relative content of oxygen, carbon dioxid and other gaseous ingredients, are now of less concern to the hygienist than are certain other factors formerly looked on as somewhat incidental. The movement of the air, and its temperature and humidity now likewise call for careful attention and analysis. To a certain degree these features are interrelated and may properly be considered together.
Inasmuch as the temperature of the body is regulated by the loss of heat through evaporation of water