It is natural that if we practice these exercises in the fresh air of the forests or mountains their salutary action will be still more pronounced. But if we are too indolent to perform the regular breathing exercises, whose beneficial effect upon the heart’s nutrition and action is so great, it will suffice for us to take deep inspirations and expirations while walking. We must get into the habit of doing this every day, and thus prolong our life. As a general rule we only breathe with one part of our lungs, sadly neglecting the other, by which the aëration of the blood will not be so thorough. Independently even of the breathing exercises, it would be very advantageous to our health if we gently took a long breath, which should be so prolonged that we feel our stomach distended. The air will thus reach the deeper portions of our lungs. This will also be the best practice while singing; indeed, the latter would be the very best of ways in which to obtain a good and thorough aëration of the lungs. We have heard of cases where people without a voice have taken singing lessons, for the simple reason that they were descended from families in which tuberculosis was hereditary. This latter disease is one of the most frequent causes of a shortened existence, and it is, therefore, our duty to point out here the great advantages not only of a generous diet, consisting of a certain amount of underdone fresh meat, uncooked milk of healthy cows or goats, and many eggs, sausages and puddings made of the blood of pigs (see Chapter XXXIX), but also of regular deep breathing, thereby permitting of the entry of oxygen to all parts of the lungs. We always recommend breathing through the nose, as doing so through the mouth dries up the mucous membranes, especially if throughout the night, during sleep, the mouth is kept open. This bad habit permits of the entrance of cold air which, not being warmed by passing through the nasal passages, may be injurious to the lungs. The Indians are fully cognizant of this fact, for in some tribes the mother binds up the mouth of her child and thus compels it to breathe through the nose. In the foregoing we have shown the great advantages of abundant fresh air. We have referred to the fresh appearance of country people, especially of those who live on mountains, as also to the improved condition of tuberculous persons after having been exposed to as much fresh air as possible. I ask, therefore, why, if people suffering from this disease derive so much benefit from fresh air, should not we, who are still healthy, be also benefited by it? Let us therefore remain in the open air as much as possible, and never prevent its close approach to us; for it gives health, long youth, and a good old age. ------------------------------------------------------------------------ CHAPTER XXXII. ON THE DANGERS OF LIVING IN CONFINED AND ILL VENTILATED QUARTERS.