This section is from the book "Practical Dietetics With Special Reference To Diet In Disease", by William Gilman Thompson. Also available from Amazon: Practical Dietetics with Special Reference to Diet in Disease.
In all serious cases the stools should be examined, if possible, microscopically, to determine the degree of digestion and absorption of the food. The chief abnormal ingredients are fat, bacteria, mucus, casein, starch, and, if meat has been eaten, muscle fibres. The green diarrhoea of infancy is usually of microbic origin. Diarrhoea of putrid character is due to albuminous fermentation, and produces more severe symptoms (see ptomaine poisoning) than those produced by the simple fetid stools of starch fermentation.
The normal percentage of fat which the stools contain is, according to Uffelmann's analysis, fourteen on the average, but in diarrhoea with intestinal dyspepsia it rises often to forty or fifty, and it has reached sixty-four. The fat appears in minute white flocculi, varying in size from that of a pin's head to a split pea. These small masses are often mistaken for casein, but the careful researches of Wegscheider, Baginsky, and others have demonstrated them to be composed of inspissated fat and colonies of bacteria. It is an easy matter to distinguish them from casein, as they alone are dissolved by the addition of a few drops of alcohol and ether.
The commonest bacteria of infant stools are the Bacterium lactis aerogenes and the Bacterium coli commune. In fact, these two normal varieties are the only constant kinds in milk-fed babies (Escherich), although Booker has found in different cases of infantile diarrhoea, and especially cholera infantum, forty varieties in all which bear no special relation to particular foods. The first-named germ occurs only when milk has been ingested, for it thrives, as its name indicates, upon lactose. Its chief site is the small intestine, where it causes milk to ferment. The Bacterium coli commune, on the contrary, elects the large intestine and thrives upon the residue of digested food. Booker is of the opinion that the influence of the various pathogenic germs in the production of diarrhoea is attributable more to alteration of the food and intestinal contents than to direct irritation of the intestinal wall.
Undigested casein is a less common ingredient of the stools than was supposed before the above-described observations were -made. When present it is in the form of smooth, somewhat hard masses, often of a yellow or yellowish-white colour without, but white when broken open. They are usually friable, and have a cheesy odour. They may present a semi-transparent or horny appearance.
They are recognised by the microscope, and by the addition of a solution of iodine, which colours the stools dark blue.
Muscle fibres are easily recognisable by microscopic examination, but not otherwise.
The principles of dietetic treatment of simple bacterial or mycotic diarrhoea occurring in infants under two years of age are, first, to give the alimentary canal rest, and, secondly, to give food which is very thoroughly absorbed, leaving the least possible residue of waste. All food is to be withheld for a few hours, and cool sterilised water or barley water, and cracked ice (if pure) is given to allay thirst. The child will not suffer from lack of food. It will suffer much more with it. If stimulants are needed, ten to thirty drops of brandy, well diluted, may be prescribed.
After the interval of rest food is to be cautiously administered, but in less than the usual quantity-. Unless the infant can have breast milk, which is usually most desirable for it, it is best to give no milk at all, but instead such articles as whey, thin mutton or chicken broth, barley gruel, or egg albumen beaten in half a pint of cold water to which a teaspoonful of brandy and a pinch of salt are added. After two or three days of this diet, if the child continues to improve, the milk diet given before the illness is to be gradually resumed, but the feeding should be watched for at least a week.
To older children, when diarrhoea has been excited by eating improper food, unless the bowels have been already very thoroughly evacuated, or if signs of intestinal irritation continue, it is best, as with adults, to give castor oil and opium in the form of paregoric or Dover's powder, and then to feed the child upon the principles laid down above for infants. As a rule, it is best to avoid "prepared foods "or patented infant foods, and good nutritious home-made fresh broth from lean mutton, or chicken, or beef, is to be preferred.