We pass from the more acute disturbances of the stomach to those more chronic affections in which the functions of the stomach and bowels are interfered with. In many cases the correction of errors in diet will serve to restore the disordered functions. In others one has to employ for a time a special diet, suited to the individual case, in order first of all to rest the stomach and bowels and allow of the gradual recovery of the disordered secretions.
In the case of breast-fed infants chronic gastro-intestinal indigestion is not common, save from gross neglect of the rules of feeding. In the case of bottle-fed babies the condition is an extremely common one, and may call for much skill and patience in treatment. The great cause of chronic indigestion in babies is overfeeding. Whenever the infant cries the tendency is to assume that he is hungry and to give more food. The very temporary relief produced by this is soon followed by more discomfort, more crying, and more food. Even if the food is vomited, it is thought that the loss must be made up, and so more food is given. The marvel is not that the child does not thrive, but that he manages to survive. Sooner or later the overtaxed digestive powers break down. The infant wastes, becomes restless and peevish, and sleeps badly. Colicky pains, vomiting, flatulence, diarrhoea or constipation, and offensive motions with mucus or undigested milk are common accompaniments.
One must make a thorough inquiry into the history of the past feeding. The freshness of the milk, the cleanness of the feeding-bottles, the amount of diluent, cream, and sugar used, the temperature of the milk, the frequency of the meals, the time spent at a meal, the state of the appetite - all these points must be inquired into so as to detect any fault which may have originated or maintained the indigestion. One of the most prolific sources of intestinal trouble in infancy is the use of condensed milk and proprietary " infants' foods." These foods are easily prepared, do not quickly go bad, and "stay down" as a rule without much difficulty, so that by a large number of ignorant mothers they are preferred to fresh foods. The infants apparently thrive on them for a time, become fat and beautiful in the maternal eyes, and are duly admired by relatives. They are not, however, suited to an infant's digestive powers, and being largely composed of sugar and starch, they tend to ferment in the intestine, so that flatulent indigestion is a common result. As we are not yet able to adapt an infant's digestion to the ideas of artificial food manufacturers, the best plan for the present is to follow the guidance of nature as far as possible. The safest and the simplest method of treatment in these cases of patent food indigestion is to discard the food altogether and to return to physiological feeding.
In the presence of chronic gastro-intestinal catarrh which does not yield to simple dietetic treatment, or which is in an advanced stage, some modifications in the ordinary feeding are called for. Further dilution of the milk may be tried. One part of milk may be mixed with two or three or four parts of lime-water, and given in small quantities every two hours by day and every four hours by night. In some cases it will be advisable to give nothing but lime-water during the night so as to rest the alimentary tract more thoroughly. As toleration is established, the strength of the milk mixture may be gradually increased. In other cases the citrate of soda method, as suggested by Wright and practised by Poynton, seems to be of service. It consists in the addition of citrate of soda to the milk, one or two grains to each ounce of milk in the mixture as diluted for use with plain or barley-water. The curds formed in the stomach are believed to be rendered more digestible, and the vital properties of the milk are not injured in any way.
Special measures may be required to overcome the indigesti-bility of the proteins of cows' milk. For this purpose whey may be used. It is prepared by adding a drachm of liquid rennet to half a pint of warm milk. After the mixture has been thoroughly stirred it is allowed to stand until firmly coagulated. The curd is then broken up thoroughly and the whey is strained off through muslin or a strainer. When whey is kept any time, or is to be mixed with other food, it is advisable to heat it to 160° F. in order to destroy the rennet ferment. One can begin with equal parts of whey and water, and give small quantities every two hours by day. Whey is usually well tolerated by the youngest infants, and one can gradually increase the strength of the food by giving it undiluted, then by the addition of some sugar or malt, and later of cream. The protein element in the diet may be increased by adding ten to fifteen drops of raw meat juice or white of egg to each feed or alternate feed. Another method of meeting the difficulty which these patients have in digesting the milk albumins is by the use of peptonized milk. This may be done by a pancreatic extract, or by peptonizing powders, or by peptogenic milk powders. The details of the method of preparation are supplied with each packet. The last named is the most suitable for young infants, as the resulting product resembles closely breast milk in its chemical composition. As a rule the peptonizing process should not be prolonged beyond half an hour, and whole milk without any extra cream should be used. Infants take and digest peptonized milk well, but its nutritive properties are certainly inferior to those of fresh milk. As the digestion improves the peptonizing time should be gradually reduced from thirty to twenty and ten minutes.
Sometimes the fatty element in the food is the cause of indigestion. This may arise either from an excessive amount of fatty material having been given, or from the special difficulty which the infant has in digesting fat. In the former case a reduction in the amount of fat in the diet will probably effect a cure. The symptoms associated with fat indigestion are vomiting, toxaemia, and possibly convulsions. An excess of fat may be found in the stools, which are offensive, white or grey in colour, and contain small yellowish masses which are often mistaken for curds. These masses may be distinguished from curds by the facts that they are soluble in ether and burn readily with an odour of butter (Holt). The fat of cows' milk may be the source of trouble, and Finley Bell suggests in such cases the use of goats' milk, in which the fat more closely resembles that of breast milk. Stern believes that the high percentage of volatile fatty acids in cows' milk as compared to human milk is the cause of fat indigestion. He recommends the addition of yolk of egg to skimmed milk suitably modified. Yolk fat yields very little fatty acid, and the large amount of lecithin which it contains acts as a stimulant of the whole nervous system. An average yolk contains about six grammes (90 grains) of fat, so that roughly speaking, an ounce of (20 per cent) cream corresponds to one yolk as regards fatty content. The yolk should be perfectly fresh and given raw.