The bowels do not move without a reason for moving. The pelvic colon is an ejecting apparatus for expelling fecal residues, which works only when brought into action by the reflex nervous mechanism which comprises the nerves of the rectum, the defecating center, and the connecting nerve trunks. The entrance of food into the rectum is like the closing of a switch which controls the starting and stopping of a motor. When the rectum is distended, the nerves are stimulated, and in turn excite the defecating center where they originate. From this center are sent out impulses which cause the pelvic colon to contract strongly and empty itself. In doing this it is assisted by strong contractions of the abdominal muscles and of the rest of the colon.
This process, it must be remembered, is set in operation only when there is a sufficient movement of feces from the pelvic colon, where the feces are stored, into the rectum, to produce the necessary amount of stimulation. As we have already seen, this is accomplished, normally, by peristaltic movements set up by taking into the stomach relishable food. In constipation, these stimulating reflexes are often weak, and must be reinforced by every means possible. Hence the diet must be so managed as to secure the maximum amount of stimulating influence upon the lower bowel. Eternal vigilance is necessary; every meal must be taken with reference to the bowel action. A single omission of a meal, or a meal of unsuitable food, may be sufficient to produce an undue accumulation of feces in the colon and rectum, and unless this is immediately corrected, the most serious results may follow. The taking of food, then, serves a double purpose, it supplies the body with needed nourishment and at the same time furnishes the impulse needed to enable the body to get rid of the unusable residues of a previous meal and of a portion of its constantly accumulating intestinal excretions. So if regularity of bowel movement is to be expected, care to take the food at regular intervals becomes a matter of absolute importance. With the savage, regularity of bowel movement is not a matter of so great importance, for the reason that he is rarely so situated that he cannot respond quickly to the "call" for evacuation. But civilized human beings by their systematic and, in general, their closely occupied life, must often find themselves in circumstances which compel a considerable delay in answering the "call" without being seriously incommoded. Rather than interrupt the normal rhythm, even on a single occasion, it would be better to incur a very considerable degree of inconvenience, a fact which the constipated must take to heart and carry in mind; but it is better to observe such an order of life and such regularity of habits as will cause the bowels to move at a time at which they may without haste or inconvenience receive the leisurely and thorough attention which the importance of this function demands.
Every meal must contain foods which will leave a sufficient amount of residue to prevent stagnation. To neglect this fact on a single occasion may in the case of a constipated person, who by careful attention to regimen has established regular bowel habits, cause the beginning of a return of all the old conditions.
Too much emphasis cannot be laid upon the absolute and unfailing faithfulness required to maintain the improved condition which may have been attained. The majority of cases of constipation relapse sooner or later, but chiefly because patients return to their old irregular and careless habits. Drugs are resorted to because by their use the difficulty is temporarily overcome with so much less trouble and self-control than is needed for the complete regulation of one's habits of life, especially in relation to eating. Sufficient care in the matter of diet will be followed by success in nearly all cases of simple constipation. It is necessary, however, that the proper regimen should be strictly and uninterruptedly followed.
The act of defecation must be made as complete as possible. The rectum and lower bowel are often filled with dry feces which are an obstacle, the removal of which by patient and continued effort may be followed by a full and natural movement.
Sometimes a partial movement will be followed by another, within a half hour or less. Many persons evacuate their bowels in the morning by two movements, one on rising and the other soon after breakfast. Whatever may be the vagaries of the individual colon, if it can be persuaded to act at all, other things must be accommodated to its needs. In many cases, always when the movement seems less complete than usual, it is wise to give the bowels a second opportunity for movement a few minutes or half hour later. If a second "call" is experienced, the matter should not be ignored, but should receive instant attention. The moving of the bowels is a matter of equal importance with the taking of meals, and should be given the same consideration. A crippled colon must be humored and coddled, so to speak, and in many cases apparently hopeless the result may be in time that the colon may be trained back to habits of normal activity and regularity.