In some cases of intestinal disturbance a proprietary food may be a great boon, or while the mother is traveling and is unable to have freshly prepared milk formulas supplied to her along the way. These foods may be valuable, also, during the summer, while one stays at a hotel or boarding house where the freshness, cleanliness or purity of the milk are uncertain, or during a sudden shortage of fresh milk, as may occur during a strike or severe storm when transportation is interrupted. But you should not use a prepared infant food for any length of time without your doctor’s order. If you are confronted with the necessity of choosing a prepared food, for temporary use, you may be guided by considering the general objects and principles of baby feeding and the character of the various foods at your disposal. =The proprietary foods= may be divided into two general groups: one kind contains milk powder and is usually added to water, while the other consists largely of sugar and starch and is added to fresh milk before being given to the baby. =Canned milk= is of two kinds; evaporated, which is unsweetened, and condensed, which is sweetened. _Evaporated milk_ is whole milk from which part of the water has been removed, the milk then being canned and sterilized. The addition of water to evaporated milk restores it to the composition of whole milk in many respects, but it is still milk that has been heated. _Condensed milk_ is evaporated milk to which cane sugar has been added to aid in its preservation. Since bacteria do not grow well in highly sweetened foods, it is not necessary to bring sweetened condensed milk to as high a temperature as the unsweetened product, to prevent subsequent bacterial decomposition. The high percentage of sugar in condensed milk quite obviously renders it unsuitable for continuous use as the sole article in a baby’s dietary. =Milk powders or dried milks= are prepared by rapidly evaporating the water from whole milk, skimmed milk or partly skimmed milk, leaving the solid constituents in the form of a light, white powder. Milk powder readily dissolves in water, forming a “reconstructed milk” which closely resembles the fresh milk from which it was prepared. But it must not be forgotten that reconstructed milk has been heated. Many doctors consider whole milk powder the most satisfactory form of preserved milk which is available for baby food. Should it be used, however, the importance of keeping it tightly covered and in a cold place must be recognized, for the presence of fat renders it likely to become rancid if not kept cold. ARTICLES OF FOOD WHICH ARE SOMETIMES INCLUDED IN THE BABY’S DIETARY