In this manner are not only the voluntary muscles enlarged and strengthened, but also the involuntary muscles, particularly the heart and the diaphragm. The increased activity of the circulation stimulates other organs to increased activity. The quantity of perspiration from the skin is more than doubled, the appetite is increased, digestion is more perfect, absorption is more rapid, the hepatic circulation is more active, and the abdominal circulation is carried on more vigorously. But, on the other hand, actual harm may be done if any one who has been accustomed to lead a sedentary life, or who is not vigorous, suddenly engages in the more violent forms of exercise. In this extreme exertion the heart may be embarrassed by the respiratory action. At the end of deep inspiration the increased pressure of the lungs impedes the flow of blood from the right side of the heart, while the compression of the heart itself by the distended lungs tends to overfill the large veins, and to further endanger the right side of the heart. During general muscular contraction the arterial pressure is increased at the outset of exertion, before the arteries have become relaxed, and this in turn may lead to the engorgement of the left side of the heart and the circulation through the lungs. To these conditions may be added still another; that is, the exhaustion of the respiratory muscles, partly because of the unusual amount of labor thrown upon them, and partly from the inadequate supply of properly oxygenated blood. If the disturbance of the pulmonocardiac equilibrium be severe and the condition unrelieved, general prostration ensues long before the muscles engaged in the work are exhausted. If, on the other hand, the equilibrium be restored, or when the heart and lungs have been trained to accomplish the restitution, the distress disappears, and the individual is said to have gotten his second wind. =The Gymnasium in the Campaign against Disease.=—Women, generally speaking, do not take sufficient exercise. The trend of the present day is for girls of the richer classes to lead an outdoor life, but the women of the middle and lower classes do not obtain enough variety of exercise or enough fresh air, and to the lack of proper outdoor exercise is due their anemic condition, pallor, flabby muscles, and generally ill-nourished appearance. With the division of labor and the increase of wealth it has become possible for a large proportion of the community to live without much all-round mental or physical activity. As a consequence, there are faulty circulation and defective nutrition, the vital resistance of the body is lowered, and some of its various organs or tissues are ever ready to take on disease. The lowering of the tone of the body through dissipation, want of fresh air and sunshine, insufficient sleep, lack of proper occupation or recreation, also increases the susceptibility of the body to disease.