Swimming and sea-bathing should be avoided by persons who have weak hearts and a poor circulation, in whom the reaction after a plunge into cold water is never well established. Also by persons with heart or kidney disease, and by all feeble and old persons. Persons with feeble constitutions, but with no actual disease, as in various forms of nervous disorders, insomnia, etc., generally derive marked benefit from sea-bathing. Persons who are weak should walk and not plunge into the water. As in all other exercises, a determination on the part of the weak to equal the strong is a fertile cause of mischief. =Horseback Riding as an Exercise.=—The advantages claimed for horseback riding are that it acts on nearly every muscle of the body, while the mind is interested and refreshed. An insuperable disadvantage to the majority of women living in large towns and cities is the enormous cost of the exercise. The value of horseback riding for women has been greatly diminished by the very faulty position caused by the side-saddle, which produced a cramped position of the body and a tendency to lateral curvature of the spine. Then, too, women ride too tightly corsetted, thereby preventing much good that would otherwise accrue to the circulation and digestive organs. When the woman rides astride, the body is held erect and in a natural position, and she sits much more firmly on her horse and, if not corsetted, it becomes an exhilarating and delightful form of exercise. The best results will probably be found in a neurasthenic class of women, who are not strong enough to take more active exercise, and for them it will be of decided therapeutic value to both mind and body. =Rowing.=—This is one of the most beneficial of exercises; it has the advantages of scenery, freedom from dust, and companionship; it exercises equally both sides of the body and most of the muscles. It is an excellent exercise for strength, rapidity, and endurance. In correct and graceful rowing there is a pendulum-like movement from the hips. The rower should sit with the trunk fully extended, the head up, the eyes to the front, the chest thrown forward, and the weight of the trunk equally distributed upon the two sides of her seat. The feet rest against the stretcher, the two hands should be near together, and should be held symmetrically at an equal distance from the body. _Stretching._—The body and extended arms are brought forward as far as possible. The spinal column should be kept extended, not bent so as to make a crooked back, and the trunk should be thrown forward from the hip-joints. When the stretch has reached its forward limit, the oar is dipped into the water just far enough to cover it; then immediately the pull begins, and it must be continued evenly to the end.