So long as the bowel-content is in the region of automatic control, there is very little likelihood of trouble.  An occasional case of organic trouble—­appendicitis, lead-colic, mechanical obstruction, new growths or spinal-cord disease—­may cause a real blockade, but in ninety-nine cases out of every hundred there is little trouble so long as the involuntary muscles, working automatically under the direction of the subconscious mind, are in control.  By slow or rapid stages, on time or behind time, the bowel-content reaches the upper part of the rectum and passes through a little valve into the lower pouch.  Here is where the trouble begins.

=Meddlesome Interference.= In the natural state the little human, like the other animals, empties his bowel whenever the fecal mass enters the lower portion of the rectum.  The presence of the mass in the rectum constitutes a call to stool which is responded to as unthinkingly as is the desire for air in the taking of a breath.  But the tiny child soon has to learn to control some of his natural functions.  At the lower end of the rectum there is a purse-string muscle called the Sphincter-ani, an involuntary muscle which may with training be brought partly under voluntary control.  Under the demands of civilization, the baby learns to tighten up this muscle until the proper time for evacuation.  Then, if he be normal, he lets go, the muscles higher up contract and the bowel empties itself automatically, as it always did before civilization began.

There is, however, a possibility of trouble whenever the conscious mind tries to assume control of functions which are meant to be automatic.  Under certain conditions necessary control becomes meddlesome interference.  If the child for one reason or another takes too much interest in the function of elimination; if he likes too much the sense-gratification from stimulation of the rectal nerves and learns to increase this gratification by holding back the fecal mass; if he gets the idea that the function is “not nice” and takes the interest that one naturally feels in subjects that are taboo; or if he catches from his elders the suggestion that the bowel movement is a highly important process and that something disastrous is likely to happen unless it is successfully performed every day; then his very interest in the matter tends to interfere with automatic regulation, and to cause trouble.

Just as people often find it hard to let go the bladder muscle and urinate when in a hurry or under observation, and just as an apprehensive woman in childbirth tightens up the purse-string muscle of the womb, so the little child, or the grown up who catches the suggestion of difficulty in the bowel movement, loses the trick of letting go.  Instead of merely exercising control by temporarily inhibiting the function, he tries to carry through the process itself by voluntary control—­and fails.  Constipation is a perfect example of the power of suggestion, and of the troublesome effect of a fear-idea in the realm of automatic functions.