Digestive System.
In the stomach the food meets with the gastric juice, which has the property of turning proteid (see Diet for the various substances contained in food) into material ready for assimilation. The walls of the stomach are muscular, and their contraction churns the food with the juice. The gastric juice is secreted by glands embedded in the walls of the stomach, and is poured out when food is taken.
The whole food, now in the form of a paste, passes into a pipe about 12 inches long (the Duodenum), into which pours the secretion of the pancreas and that of the liver (bile). The pancreatic juice acts upon the starch which has escaped the action of the saliva, and also continues the work of the stomach. It furthermore emulsifies the fat or divides it into extremely fine drops.
The food passes now into a long coiled pipe—the small intestine. This secretes the intestinal juice which further assists the pancreatic juice. Absorption has been proceeding from the stomach onwards (see Assimilation). The mass of undigested food is pushed along the small intestine by means of muscles in its walls and passes into the large intestine where a similar process to that of the small intestine goes on, the remains of the food ultimately reaching the vent in a semi solid form, consisting of the undigested part and the débris of digestion.
During this complex process much blood and energy is needed for the abdominal region, therefore hard work or exercise should not immediately follow a meal. It will be noticed that each stage of digestion prepares the food for the next stage e.g., the mouth prepares the food for the stomach. Now, as the food ceases to be under our control when it leaves the mouth, every effort should, as we have said, there be made to prepare the food for its reception by the stomach. Chew food dry as far as possible, for that excites saliva. It is best not to drink till after the meal. The digestive powers often become weakened in advancing years, but may be greatly preserved, and even restored to health after long debility, by careful attention to the above hints.
Drinks made of lemon juice or orange juice and water are often very good to help an invalid digestion, but nothing is better than sips of hot water for some time before a meal. Distilled water is especially a most valuable drink. Cooling applications to a fevered stomach and warm fomentations to a cold one will often promote digestion marvellously. The feet and legs may be fomented if cold while the cold cloth is pressed over the stomach, especially if the process be long continued. Where heat is necessary it should be gradually and cautiously applied, so that sickening the patient may be avoided. (See also Assimilation, Food in Health, Indigestion).
Diet, Economy in.—Dr. Hutchison, one of our greatest authorities on the subject of Dietetics, has well said—
"The dearest foods are by no means the best. 'Cheap and nasty' is not a phrase which can be applied to things which you eat. A pound of Stilton cheese at 1s. 2d. contains no more nutriment than a pound of American cheese at sixpence. A given weight of bloater will yield more building material than the same quantity of salmon or sole.
"The upper classes in this country eat too much. The labouring classes are insufficiently fed—much worse fed than their brethren in America. One of the chief consequences is an undue craving for alcoholic stimulants; another is that our poor are not properly armed against tuberculosis and epidemic disease.
"How can this be rectified? Anyone who knows anything about the poor man's budget knows that he already spends as much on food as he is able. As it is, 50 per cent. of a workman's wages are absorbed in its purchase, so that half the struggle for life is a struggle for food.