=Colds prevented.=--A person who is able to warm himself by friction during an air bath, in a fairly cool room, renders himself practically immune to colds. Colds cause catarrh, tonsilitis, bronchitis, pneumonia, pleurisy. Pneumonia causes consumption. If one can prevent taking cold he will escape many of the ills of life. In addition to this, when the skin performs its functions properly and the internal organs are doing the same, the person is practically immune to acute contagious diseases. The air bath should be taken in a room that is properly ventilated. If the friction is performed vigorously, with the mouth closed, this will enforce deep, nasal breathing. This will prevent catarrh, enlarged tonsils and adenoids, and, if continued long enough, will cure mild cases and will assist in the cure of all cases. =Rules for physical exercise.=--Physical exercise should not be taken for one hour after a hearty meal. The best time for exercising is immediately after arising each morning. If one desires to take a cold or warm bath, he should take the air bath first. Following the water bath, he should rub his body with his hands and a Turkish towel until a warm glow is felt all over his body. Then should follow his physical exercise. The lightest dress compatible with decency and comfort should be worn during the exercises described in this chapter. He should not continue any exercise to the point of excessive fatigue. Breathing pauses will frequently be required at first, but these intervals will be less frequent as the lungs develop. =Value of physical exercise.=--The beneficial effects of physical culture cannot be overestimated. It strengthens and develops the muscles. It restores the natural functions of the skin. By exercising the muscles of the external organs of the body, exercise is given to the muscles of the internal organs. By restoring the natural functions of the skin and giving normal exercise to the internal organs we correct the functional disorders of the digestive system, the heart and the lungs, and restore to them their natural functions. The good effects will be noticed, in some ways, from the start; in other ways several months may be required. [Illustration: EXERCISE NO. 1.--Reclining on right side and raising left arm, with dumb-bell in hand and elbow rigid from hips to high over head. Same exercise with right arm while reclining on left side. Inhale deep breath as arm goes back.] =Exercise No. 1.=--Reclining on right side raising left arm, with dumb-bell in hand and elbow rigid from hips to high over head. Repeat this some ten or fifteen times. Now turn on the right side and repeat this exercise with the left hand. Inhale a deep breath each time as the arm goes back. This exercise helps to expand the chest walls and to develop certain muscles of the arms and side. It is especially valuable for one who feels debilitated, and is of value in several phases of heart disease.