Rectal alimentation must be resorted to whenever food cannot or will not be swallowed, cannot be retained in the stomach, causes intense pain in throat or stomach, when too little can be taken by the mouth to maintain strength, or when food is not absorbed from the stomach or passed on into the intestines, as when there is cancer of the pylorus, or when it is desirable to rest the stomach, as in cases of gastric ulcer and severe gastritis.

The power of the rectum to absorb foods has been studied carefully. Peptone is well absorbed from it. So is white of egg, provided a little salt is mixed therewith. Raw beef-juice is also completely absorbed. Milk proteins and gelatin are not well absorbed. Sugar is easily absorbed, but is especially likely to provoke diarrhea, or at least its quick expulsion; for in concentrated solution it irritates the mucous membrane of the bowel. It should not be introduced into the rectum in more than from 10 to 20 per cent, solutions. Starch is quite as perfectly absorbed as sugar and is not irritating. Fats are poorly absorbed. It is evident, therefore, that the best ingredients of which to make nutritive enemata are peptones, albu-moses, eggs with salt, raw beef-juice, and starch. How it happens that undigested egg-albumen, meat-juices, and starch are perfectly absorbed from the rectum has not yet been explained. Probably the epithelial cells of the mucous membrane are capable of modifying them chemically. It has also been shown that a reversed peristalsis takes place, and that food introduced into the rectum reaches the small intestine if there is no obstruction in the intestinal tract.

Not more than a large cupful (250 c.c, or eight ounces) of liquid food should be put in the rectum at one time, and the nutritive enema should not be repeated oftener than every six hours. The food should be warmed to the temperature of the body before it is administered, and should be introduced slowly. The best way is to pass into the rectum ten or twelve inches of soft-rubber catheter, to which is attached a rubber tube and a funnel or bag that will hold eight or ten ounces of fluid. It is best to use a large catheter, or preferably a colon tube of about 3/8 inch in diameter, and sufficiently thick to prevent recurvation. This can be attached directly to the funnel or reservoir. Before the catheter is inserted into the rectum the whole tube must be filled with the fluid to be used, so that no air will be forced into the bowel. By raising the funnel two or three feet above the level of the patient the enema will slowly enter the bowel. The fluid can be made most readily to flow high up into the colon, and can be retained best if the patient lies upon his left side, with his hips slightly elevated upon a pillow, and with his knees drawn up. After the fluid has been placed in the bowel, the catheter should be slowly and gently removed and pressure with a clean towel made against the anus to help the patient to hold the enema. The patient should lie still for an hour. If these nutritive injections are not well retained, a little opium may be added to the mixture.

Nutritive enemata can be given as water and saline enemata are frequently, continuously by the drop method described on page 11. From a vessel one and one-half or two feet above the patient the enema is conducted into his rectum by a rectal tube in which there is a stopcock which can be so set that the fluid will flow into the rectum drop by drop. The enema must be kept at body temperature. It is usually well absorbed when given in this way.

Although food can successfully be given by the rectum, enough cannot be given to maintain strength fully. Food that will generate more than 500 calories daily cannot be administered by enemata. This is from one-fourth to one-fifth of what an adult needs.

Enemata are best absorbed if the bowel is kept clean; therefore, at least once daily the colon should be flushed. The addition of common salt also contributes greatly to the readiness with which nutritive injections are absorbed.

The articles of food most frequently used for rectal alimentation are peptonized milk (see p. 79) or peptonized milk to which white of egg or starch and salt are added. Leube recommends formulas like the following:

Peptone...................... 60 grams (2 ounces)

Milk......................... 250 c.c. (8 ounces).

3 eggs

Salt......................... 3 grams (314 dram)

Milk......................... 250 c.c. (8 ounces).

Grape-sugar.................. 60 grams (2 ounces)

Milk......................... 250 c.c. (8 ounces).

Starch....................... 60 grams (2 ounces)

Milk......................... 280 c.c. (9 ounces).

Leube has also advised a pancreas enema made by mixing 60 grams (2 ounces) of minced pancreas, 200 grams (7 ounces) of minced meat, and 30 grams (1 ounce) of fat. It is supposed that the pancreas and its juices will aid digestion in the colon.

A good nutritive enema can be made of the whites of three or four eggs, two ounces of starch, a teaspoonful of salt, and eight ounces of water. To this may be added, if desired, pancreatic extract and sodium bicarbonate. Nutritive suppositories have also been made, but, although easily administered, they do not furnish so much nourishment nor are they so perfectly absorbed as are enemata.