If I were to add to this lecture a paragraph of practical hints, I would say, first of all, keep your houses and offices cool, never above and usually well below 70° F. Unfortunately here a difference between men and women sometimes causes trouble. Woman possesses a perpetual blanket of adipose tissue between her skin and her muscles, which is usually less developed in man, and hence women can dress more thinly than men, and are usually comfortable at a lower temperature. I have seen more than one happy home in danger of wrecking from this unfortunate difference. As a married man I am tempted to plead for greater charity on the part of wives; as a physiologist I realize that a lower temperature is more healthful. Keep room air in motion. An electric fan or a current of air from a window is a great aid in keeping down one's bodily temperature, and preventing sleepiness and bodily discomfort from stagnant air; with electric fans in use there would be fewer naps in churches and lecture halls. Air in motion promotes efficiency. Accustom yourselves to draughts, and especially big draughts. A small blast of cold air directed against a small area of warm skin may do harm, but the larger the current the more the harm gives way to benefit. Air of constantly uniform temperature is monotonous and debilitating. An occasional and considerable cooling, a flushing of the room by a sudden large inrush of outside air is, like a cold bath, stimulating. Do not be afraid of opening the windows of sleeping rooms at night. The prejudice against night air, which arose naturally enough from the belief in the existence of nocturnal disease-bearing miasms, in the light of present knowledge is a foolish prejudice and must give way to the rationalism of scientific fact. The increasing employment of cool outdoor air both night and day as a therapeutic agent in the treatment of disease is based on scientific principles and is justified by its results. And, finally, the whole moral of the modern physiological doctrine of fresh air may be expressed tersely in the two short words, keep cool.
I have thus endeavored to present to you a fair picture of the present attitude of science toward the problem of fresh air and its relation to health. Such a consideration 'affords an unusually fruitful opportunity to witness the ways in which science progresses, forming hypotheses, testing them and then retaining, rejecting or refining them, as the evidence derived from observation and experiment warrants. Of the subject before us there are still many gaps in our knowledge, and these gaps must be filled. Present knowledge is never final, and our present ideas of what constitutes fresh air may yet require revision. There has recently been brought together in the City of New York under the influence of the Association for Improving the Condition of the Poor and with governmental recognition a group of representative men of science
