the time being, retarded, but when relaxation occurs the blood flows
into its vessels more freely than if no momentary cessation had taken
place. When the body or any of its parts is deprived of motion, the
blood circulation stagnates, and the nutrition, general or local, as
the case may be, promptly becomes impaired. This is specially true of
the uterus. Gentle but constant motion is absolutely essential to keep
up a healthy uterine blood circulation. Nature has provided for the
automatic performance of all the ceaseless internal motions that are
necessary to the continuance of life and the preservation of health;
thus the heart beats, the respiratory muscles act, the stomach
executes a churning motion during gastric digestion, the intestines
pass on their contents by worm-like contractions, automatically
without our supervision and without causing fatigue, being under the
control of the sympathetic system of nerves chiefly. It is equally
true, but not so well recognized, that the previously described
motions that are committed to the pelvic organs from the respiratory
apparatus are absolutely necessary to the continued health of the
uterus and its appendages. But the womb is not under the control of
the voluntary muscles, therefore it cannot be directly moved by them,
nor are its necessary motions influenced by the sympathetic system of
nerves as are the heart, stomach, and intestines, etc., but it is
fortunately under the indirect but positive control of involuntary
muscles that never, as long as breathing continues, cease their work.
Nature has thus made ample provision to keep the uterus in automatic
motion. As before stated, the natural ceaseless heavings of the lungs,
chest, and diaphragm, aided by the muscles inclosing the abdomen, have
the duty assigned them of communicating automatic motion to the uterus
and the other contents of the pelvis. When the diaphragm descends from
A to B, and the lungs are filled with air, the uterus sinks in the
pelvic cavity in obedience to the downward pressure from above, as