The ancient terror, however, still clings, with a hold the more tenacious as it becomes narrowed, to one large group of these calamities believed to be produced by cold,--namely, those diseases supposed to be caused by exposure to the weather. Even here, it still has a considerable basis in fact; but the general trend of opinion among thoughtful physicians is that this basis is much narrower than was at one time supposed, and is becoming still more restricted with the progress of scientific knowledge. For instance, fifty years ago, popular opinion, and even the majority of medical belief, was that consumption and all of its attendant miseries were chiefly due to exposure to cold. Now we know that, on the contrary, abundance of pure, fresh, cold air is the best cure for the disease, and foul air and overcrowding its chief cause. An almost equally complete about-face has been executed in regard to pneumonia. Prolonged and excessive exposure to cold may be the match that fires the mine, but we are absolutely certain that two other things are necessary, namely, the presence of the diplococcus, and a lowered and somewhat vitiated state of bodily resistance, due to age, overwork, underfeeding, or over-indulgence in alcohol.
Not only do these two diseases not occur in the land of perpetual cold, the frozen North, except where they are introduced by civilized visitors,--and scarce a single death from pneumonia has ever yet occurred in the crew of an Arctic expedition,--but it has actually been proposed to fit up a ship for a summer trip through the Arctic regions, as a floating sanatorium for consumptives, on account of the purity of the air and the brilliancy of the sunlight.
There is one realm, however, where the swing of this ancient superstition vibrates with fullest intensity, and that is in those diseases which, as their name implies, are still believed to be due to exposure to a lowered temperature--"common colds." Here again it has a certain amount of rational basis, but this is growing less and less every day. The present attitude of thoughtful physicians may be graphically indicated by the flippant inquiry of the riddle-maker, "When is a cold not a cold?" and the answer, "Two-thirds of the time." This much we are certain of already: that the majority of so-called "colds" have little or nothing to do with exposure to a low temperature, that they are entirely misnamed, and that a better term for them would be _fouls_. In fact, this proportion can be clearly and definitely proved and traced as infections spreading from one victim to another. The best place to catch them is not out-of-doors, or even in drafty hallways, but in close, stuffy, infected hotel bedrooms, sleeping-cars, churches, and theatres.