The person who takes vigorous exercise in the open air such as playing games like tennis or golf, or who walks vigorously, will have no need for formal breathing exercises. For those, however, who cannot readily obtain outdoor exercises the natural way, the following chest movements and breathing exercises are recommended. They should be taken with the body free from tight clothing, and either in the open air or a well-ventilated room. First, raise the hands above the head as far as they can reach, and then bring them forward and upward several times, and then upward and downward on the side of the head, inhaling on the uplifting of the arms, exhaling on the sinking of the arms. When the arms are lifted above the head, opportunity is given for the air inhaled to reach the upper part of the lungs, parts which in the sedentary person are very rarely used, and where usually the germs of tuberculosis begin their evil work. Arm extension forward, breathing deeply with arms carried sideward and backward, at shoulder height. If those who exercise in their rooms will be careful to breathe only through the nose and will keep the head erect, they will find that the performance of almost any set of exercises will serve also as breathing exercises, since they will increase lung activity. XIII BATHING AND CLEANLINESS The soldiers of the body which carry on for us the battle against disease, old age, and death, have as great and as constant a need of water as do the human soldiers, part of whose equipment is always the indispensable canteen. Water is needed by the body in many ways, but it is especially required by the blood. Water is the solvent in which float the white and red corpuscles of the blood, and the many nutritive elements which the blood carries through the body, and the particles of waste material which it bears to the lungs to be burnt up, or to the other excretory organs to be ejected. By the aid of water, the minute particles of food which are broken up and transformed by the chemical processes of the body are conveyed to the most distant fibre of the intricate human mechanism, wherever repair or new growth is required. No other element of nature could so well carry on this function as water. It is so limpid and mobile that it can move through the most delicate and intricate network of veins, and can find its way by osmosis or percolation into such parts as are inaccessible by openings.