This section is from the "Nature Cure: Philosophy and Practice Based on the Unity of Disease and Cure" book, by Henry Lindlahr.
The diaphragm is a large, flat muscle, resembling a saucer, which forms the division between the chest cavity and the abdominal cavity. By downward expansion it causes the lungs to expand likewise and to suck in the air. The pressure of air being greater on the outside of the body than within, it rushes in and fills the vacuum created by the descending diaphragm. As the diaphragm relaxes and becomes contracted to its original size and position, the air is expelled from the body.
(11) (To stimulate the action of the diaphragm)
Lie flat on floor or mattress, the head unsupported. Relax the muscles all over the body, then inhale deeply with the diaphragm only, raising the wall of the abdomen just below the ribs without elevating either the chest or the lower abdomen. Take about four seconds to inhale, then exhale in twice that length of time, contracting the abdomen below the ribs.
(12) (Internal massage)
Lie on your back on a bed or couch, knees raised. Relax thoroughly, exhale and hold the breath after exhalation. While doing so, push the abdomen out and draw it in as far as possible each way. Repeat these movements as long as you can hold the breath without straining, then breathe deeply and regularly for several minutes, then repeat the massage movements.
Next to deep breathing, I consider this practice of greater value than any other physical exercise. It imparts to the intestines an other abdominal organs a "washboard" motion which acts as a powerful stimulant to all the organs in the abdominal cavity. Internal massage is especially beneficial in chronic constipation. This exercise may be performed also while standing or walking. It should be practiced two or three times daily.