We have already referred to the use of barley-water as a diluent. This, if made as directed for infants, is not of any nutritive value, but is a bland fluid which diminishes, to a slight extent, the denseness of the curd in the stomach. Some able writers (Jacoby, Chapin, etc.) have recommended that stronger decoctions of cereals, barley, wheat, or oats, should be added to the milk not only as an aid to ■digestion but also for their nutritive properties. As with many other substances, it may be possible to rear infants on these decoctions, but the method is not in accordance with nature's teaching. The only carbo-hydrate in breast milk is milk-sugar, and starches do not occur in any form. Another practical difficulty in connexion with the use of these decoctions is that, although they may be prescribed in a dilute form, the tendency of the nurse will be to make them stronger and stronger, in the belief that they are so much more nourishing than milk. In the case of healthy children they are not required, and in the case of infants with weak digestion they are probably injurious.
We have now considered the various forms of modifying cows' milk which are employed in the feeding of infants. There are other food preparations on the market, each of which is recommended by the makers as a complete food for infants. There are dried milk preparations, condensed milk, and the so-called "infants' foods," usually containing more or less starch. They have been fully described in another section of this volume. Every opportunity has been seized by the public to try these food substitutes, and consequently the medical profession has also been able to test their value. All have been proved and have been found wanting. Many forms of disease are directly traceable to their prolonged and exclusive use. As regards healthy infants, therefore, these foods should not form part of the diet up to the age of nine months. After that age they may be employed in moderation as a part of the diet. The question of • their employment in certain cases of disease and debility will be considered later.
In connexion with the subject of these proprietary preparations we may consider the meaning of the term "a complete food for infants." From the medical standpoint a complete food for infants, during the first nine months, must fulfil the following requirements. It must contain the various elements, proteins, fats, and carbo-hydrates, which are found in breast milk, in a proportion suited to an infant's digestive powers, and in amount sufficient for the requirements of all the growing tissues. Per contra, it must not contain elements which are not found in breast milk, and which are not suitable to an infant's digestive powers. It must consist of fresh or living food, which means that it must not have lost its freshness through keeping, or prolonged heating, or drying, or predigestion. It must be free from extraneous organisms, or contain them only in such numbers as not to affect injuriously the food or the gastro-intestinal mucous membrane. It must not, in the process of preparation, be treated by mechanical or other means, as to alter the component elements and render them unsuitable for digestion.
Were some such standard adopted in connexion with the feeding of healthy infants, a number of foods which are now largely-used would be entirely abolished, with great benefit to the rising generation.