*Causes of Shallow Breathing.*—Anything that impedes the free movement of air into the lungs tends to cause shallow breathing A drooping of the back or shoulders and a curved condition of the spinal column, such as is caused by an improper position in sitting, interfere with the free movements of the ribs and are recognized causes. Clothing also may impede the respiratory movements and lead to shallow breathing. If too tight around the chest, clothing interferes with the elevation of the ribs; and if too tight around the waist, it prevents the depression of the diaphragm. Other causes of shallow breathing are found in the absence of vigorous exercise, in the leading of an indoor and inactive life, in obstructions in the nostrils and upper pharynx, and in the lack of attention to proper methods of breathing. To prevent shallow breathing one should have the habit of sitting and standing erect. The clothing must not be allowed to interfere with the respiratory movements. The taking of exercise sufficiently vigorous to cause deep and rapid breathing should be a common practice and one should spend considerable time out of doors. If one has a flat chest or round shoulders, he should strive by suitable exercises to overcome these defects. Obstructions in the nostrils or pharynx should be removed. *Breathing Exercises.*—In overcoming the habit of shallow breathing and in strengthening the lungs generally, the practicing of occasional deep breathing has been found most valuable and is widely recommended. With the hands on the hips, the shoulders drawn back and _down_, the chest pushed upward and forward, and the chin slightly depressed, draw the air slowly through the nostrils until the lungs are _completely_ full. After holding this long enough to count three slowly, expel it quickly from the lungs. Avoid straining. To get the benefit of pure air, it is generally better to practice deep breathing out of doors or before an open window. By combining deep breathing with simple exercises of the arms, shoulders, and trunk much may be done towards straightening the spine, squaring the shoulders, and overcoming flatness of the chest. Though such movements are best carried on by the aid of a physical director, one can do much to help himself. One may safely proceed on the principle that slight deformities of the chest, spine, and shoulders are corrected by gaining and keeping the natural positions, and may employ any movements which will loosen up the parts and bring them where they naturally belong.(36)