Page:Popular Science Monthly Volume 54.djvu/817

Rh process. Summarized in a few words, it is simply to warm, moisten, and clean the air which we inhale.

The healthy nostrils are anatomically and physiologically so formed that when the current of air passes through them it will have been freed of its mechanical impurities, warmed to within a few degrees of the temperature of the body, and moistened to saturation. This has been experimentally demonstrated.

The opening of the passage of the ear into the throat has several objects, the most important being ventilation and the adjustment of the atmospheric equilibrium. This passage leads outward until it enters the cavity of the middle ear, which is closed by the drum on the outside, thus separating it from the external canal of the ear. We know that atmospheric pressure varies at different times and in different altitudes. It is much less, for instance, at the top of a mountain than at the seaside. The opening into the throat allows the air to enter, and adjusts the atmospheric pressure within the ear to these various external conditions. Those of you who have ascended Lookout Mountain by means of the incline cable car may have noticed the adjustment taking place by a peculiar click when different altitudes were reached.

So intimately are the nose, throat, and ear connected that it is unusual to find one affected to any considerable extent without the others being involved. While the rules of hygiene in general are applicable to the nose, throat, and ear, there are certain special conditions which deserve consideration. One of the most common causes of injurious effects to the nose, throat, and ear is the so-called "cold." The cold in this connection is, of course, understood to be simply the cause, the condition itself being a peculiar inflammation of the parts concerned. As cold is so frequently a cause of diseases of these parts, it would be well to consider under what circumstances it develops and the best mode of prevention.

I have often noticed that persons who suffer most frequently and severely from colds usually insist that they exercise the greatest care to avoid exposure. They have dressed in the warmest clothing, wrapped the neck in the heaviest mufflers, remained in the closest rooms, and avoided every draught, and yet they continually "take cold." The street urchin, on the other hand, with only two or three garments and without shoes, and who lives out of doors, suffers less frequently from this affection.

"Colds" have truly been called a product of modern civilization. The trouble was rare among the aborigines and is more common among the cultured than among the laboring classes. If we make a plant an exotic, we must keep it in the conservatory, and even here it is not free from danger. On the other hand, if we wish to harden it and