The plain or modified milk is placed in a clean glass jar or bottle, and the peptonizing powder, which is first rubbed up with a tablespoonful of the milk, is added and the bottle shaken. The bottle is then placed in a large pitcher or basin containing water kept at the temperature of about 110 deg. F., or as warm as the hand can bear comfortably, and left for ten to twenty minutes if the milk is to be partially peptonized; for two hours if it is to be completely peptonized. _What taste has partially peptonized milk?_ None, if peptonizing is continued for only ten minutes, but at the end of twenty minutes it begins to be bitter, when the process of digestion has gone further. _How is the bitter taste avoided in partially peptonized milk?_ At the end of ten or fifteen minutes the milk may be placed in a saucepan and quickly raised to boiling point; this kills the ferment, so that the milk will not become bitter when warmed a second time. Or, the milk may be rapidly cooled by placing the bottles first in cool and then in ice water; in this way the ferment is not destroyed, and the milk may become bitter when warmed for feeding. _Should the whole day's supply be peptonized at once, or each bottle separately just before the feeding?_ Either plan may be followed. If the former, it is better to raise the milk to boiling point after peptonizing; if the latter, it should not be peptonized more than ten minutes, for it will continue to peptonize while it is being taken by the child. _Is not the bitter taste of completely peptonized milk a great obstacle to its use?_ Not in the case of young infants; one under four or five months old will usually take it without any objection after two or three feedings; but it cannot often be used for those who are much older. _How much of the peptonizing powder should be used?_ There are required for one pint of plain milk, five grains of the extractum pancreatis and fifteen grains of bicarbonate of soda. This quantity is usually put up in a single tube or tablet. In the formulas previously given, less than this will be required; for the weaker formulas, one half or one third of the powder mentioned will be sufficient for one pint of food. For a single feeding of four ounces, one may use one eighth of a tube with a weak formula, or one sixth of a tube with a stronger formula. _What are the advantages of peptonized milk?_ Partially peptonized milk is useful for young infants who have great difficulty in digesting the curd of milk, sometimes even when diluted as already described; completely peptonized milk, during acute attacks of indigestion. _For how long a period may the use of peptonized milk be continued?_ Completely peptonized milk may be used for a few days, or at most a few weeks; partially peptonized milk may be used for two or three months, but not indefinitely; it should be left off gradually by shortening the time of peptonizing, and lessening the amount of the powder used.