ABSTRACT
Preventive medicine is concerned with the prevention of disease and with the preservation and enhancement of health. Of all the diseases from which humanity suffers, the most serious and lethal are those caused by infective agents introduced from without, and preventive medicine will continue to be largely if not chiefly concerned with them. This chapter reviews the influence of conditions of air and ventilation, of temperature and humidity, of sunlight and, in relation especially to these, of housing conditions, and the influence of general sanitation. The problem of ventilation was thus proved to be physical or thermal rather than chemical, and to be concerned more with the skin than with the lungs. In short, air is unfitted for ventilation in proportion as it loses its capacity for taking up heat. As seen in Evolution of Preventive Medicine 'corruption of the air' was regarded as a chief cause of epidemic diseases.
