Respiration is altogether mechanical, depending upon the constitution of the muscles of the chest, the extension of the latter, and the quantity of air inspired. If the capacity of the lungs be increased, all difficulty of breathing, coughs, etc., caused by an imperfect respiration, will soon disappear.

In cases where defective respiration is the result of weakness of the respiratory muscles or of deformities of the chest, the movements have proved the best means for increasing the capacity of the respiratory organs.

The effect of the medical gymnastics is to necessitate frequent and deep inspirations, and thus increase the capacity of the lungs, promoting pulmonary circulation and causing a more complete oxygenation of the venous blood.