~Digestive Disturbances.~--It is a well-established fact that artificially fed infants are more subject to disturbances due to diet than breast-fed infants, the digestional disturbances of the latter yielding more readily to treatment. As a rule, with the breast-fed baby it is largely a question of adjusting the diet of the mother, of increasing the fluid in her diet, of seeing that she takes the requisite amount of exercise in the open air, and of lengthening the intervals between feedings or of giving the baby water just before putting him to the breast. With the artificially fed infant it is an entirely different proposition. ~Causes in Artificially Fed Infants.~--The digestive disturbances may arise from any one of half a dozen or more causes. The constituents in the milk may be in the wrong proportion. The amount given at a feeding may be too great or too little. The dilution may be too great or too small to meet the needs of the infant. Or the milk may contain the microoerganisms which bring about fermentation or putrefaction. Any or all of these causes may assail the artificially fed baby. Consequently, all the care that can be exercised must be resorted to in the feeding of these babies, not only after digestional disturbances arise, but as a means of their prevention. In the preceding chapter the methods generally used in the feeding of normal infants were discussed. We now proceed to the feeding under abnormal or pathological conditions. ~Errors in Diet.~--The majority of the ills from which the baby suffers can be traced primarily to ~errors in diet~ and in most of these cases the treatment consists chiefly in adjusting the formula to suit the condition. As a rule, these errors may be placed under two heads: those that are brought on by under-feeding and those induced by over-feeding. The pathological conditions arising from under-feeding are due not only to a lack of food, but chiefly to the improper balancing of the different food constituents in the formula. As has already been stated, so much food is required to cover the energy expenditures, so much for maintenance, and so much for storage for the growth and development necessary during the entire period from birth to maturity. These constituents must be regulated to the individual needs of the infant. ~Over- and Under-dilution.~--If the dilution is too great, the infant, while receiving the correct amount of the mixture, may have the necessary food constituents so reduced as to have them fail completely to do their appointed work in the body. Or if the amount of diluent is too small the baby may be receiving too strong a mixture, and develop nutritional disturbances therefrom. Under the first head the child suffers from under-feeding; the appetite is satisfied before enough of the actual food is ingested to meet his various needs. However, it is probable that the artificially fed infant suffers from the results of over-, rather than of under-feeding.