Other elements of the food besides bulk, exert a marked influence upon the activity of the digestive organs. All the sugars stimulate intestinal activity. Roger thinks this action is confined to the small intestine, but in this he is in error, for every abdominal surgeon knows the remarkable laxative effects of an enema consisting of a half pint of molasses with an equal amount of hot water.
Cane sugar is undesirable, however, because of its irritating effects. The sugars of fruits - levu-lose and dextrose - are wholesome and efficient. The malt sugar produced by the action of the saliva upon starch is of great service as a stimulant of gastric and intestinal activity. Many mothers know of the laxative effect of milk sugar added to the infant's food. Malt sugar is better, because free from germs, and more native to the body than the sugar of cow's milk.
Malt sugar, as shown by recent experiments, is absorbed in one-fourth the time required for milk sugar.
The acids of fruits and vegetables - citric, malic, and tartaric, - are excellent laxatives. This is, in part at least, the explanation of the good effects of an orange taken at night or before breakfast All acid fruits are laxative. The tomato, a vegetable fruit, is a most excellent stimulant of intestinal action, chiefly through its citric acid. When possible, the tomato as well as other acid fruits should be eaten raw, to obtain the best effects.
Lactic and acetic acids developed in the intestines by the growth of harmless acid-forming bacteria, are a powerful stimulant of intestinal action. A. Schmidt of Halle, Germany, has demonstrated that these acids are the normal stimulants of the colon. When they are present in sufficient amount, bowel activity is normal. Putrefaction produces an alkaline condition in the colon which has a paralyzing effect upon the intestinal movements. Sour milk and buttermilk produce a decided laxative effect in many persons, especially in children.
Oils and fats stimulate intestinal action. Not only fats themselves, but the glycerine and soaps which are formed by the digestion or decomposition of fats in the intestine, are very active stimulants of intestinal movements.
Mineral oil - white Russian paraffin oil - being indigestible and unabsorbable, is a very powerful stimulant of intestinal activity. It adds to the bulk of the food, lubricates the food canal, hinders the excessive absorption of water, and keeps the bowel contents moist.
The carbonic acid gas and other gases formed in the intestine by the fermentation of starch, cellulose, and other foodstuffs are powerful stimulants to the muscular activity of the bowel. When present in excess, gases cause spasm of the circular muscles of the intestine, with sharp colic pains.
The taking of food into the stomach is by far the most powerful of all the natural stimulants of the intestine. Very soon after food enters the mouth, peristaltic movements begin in the stomach, and quickly extend the whole length of the food canal. This is the reason for the desire to evacuate the bowels which most people experience soon after eating breakfast The peristaltic waves set up carry the feces down into the rectum, and this produces the sensation which indicates the necessity for evacuation.
It has been shown that even the smell of agreeable food is sufficient to cause increased intestinal activity. The act of swallowing also excites intestinal activity.
X-ray examinations show that the intestinal contents move four times as fast during a meal as during the interval between meals.
It is the opinion of the writer that bowel movements should occur after each of the principal meals of the day. This question is discussed further in a later chapter.
Pleasurable emotions and excitement have been known to produce intense activity of the intestines, and even diarrhoea, while depressing emotions have the opposite effect. This has been clearly demonstrated experimentally, in animals as well as clinically in human beings.
This powerful agent may be applied in such a way as greatly to stimulate intestinal activity. The most effective method is the application of the sinusoidal current to the rectum and abdominal muscles, or to the rectum and the central portion of the back. Another very effective method, perhaps the most efficient of all methods, is the application of a bi-polar electrode to the inner surface of the pelvic colon, which is the point of greatest delay in the majority of constipated persons.
Powerful mechanical impulses may be communicated to the intestines and the nerve ganglia which control them, by suitable apparatus. The writer has in numerous instances seen strong intestinal movements set up by this form of stimulation.
This is another valuable means of stimulating the bowel to increased activity. Kneading with the hands or with a suitable mechanical appliance has been shown to be capable of quickening the movements of the intestine, if applied with sufficient thoroughness.
Stroking, or reflex titillation of the skin, stimulates the bowel in much the same way that tickling the soles of the feet may give rise to powerful contractions of the muscles of the legs. To be effective, massage intended to influence the intestinal movements must be given by an expert.