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SATURDAY, MARCH 9, 1912
THE PHYSIOLOGIC PROPERTIES OF EXPIRED AIR
The problems of ventilation are perennial in their interest. The pendulum of hypothesis in regard to the assumed toxic properties of the atmosphere of restricted spaces has swung from one extreme to another. At the present time there is a consensus of opinion that, aside from obvious extreme alterations of the inspired air, lack of oxygen or increased concentration of carbon dioxid does not play any significant rôle in the familiar malaise of "poor ventilation." We have lately referred to the growing tendency to charge the ill effects of vitiated air to increased temperature and humidity, factors which unquestionably exert a most depressing influence under the given conditions.1Whether there are any more specific "poisons" in