There are numerous patent and proprietary foods in the market, many of which are largely advertised and extensively used by the public and the profession. It is therefore necessary to investigate their claims. These foods are made by processes of concentration, evaporation, and condensation, from meat, eggs, milk and milk products, cereals, vegetables, fruits, and nuts. In some, partial or complete predigestion of the natural food is carried out. Some foods claim to be specially suitable for feeding infants and invalids, by being made less bulky, and simpler in composition, and therefore more digestible. Others claim simply to lose their bulk, and to be suitable for travellers and the like. With regard to the value of such foods, it may be definitely stated that proprietary foods are not necessary in health, but are of very great value in cases of sickness. At the same time it should be added that the more knowledge we possess of the composition of natural and proprietary foods, and of the effects of cooking natural foods, the less often will it be found necessary to have recourse to the more expensive patent preparations. In the following pages an account is given of the leading facts in the composition and uses of the best-known proprietary foods. The data given under the heading of composition have been taken partly from the results of the analysis recorded by the makers, and partly from the analyses of the individual foods published from the Lancet and other laboratories. Proprietary foods may be classified as follows: -

Classification Of Proprietary Foods - Other Than Predigested

A. Nitrogenous Foods

1. Prepared from cow's milk. - (a) Condensed, with or without sugar; (b) dried milk preparations; (c) modified milk.

2. From meat. - Meat teas, extracts, juices, powders.

3. From eggs, usually in combination with milk protein or animal protein.

4. From vegetables, either alone or in combination.

B. Carbohydrate Foods

Starch, unchanged, or partially changed into soluble carbohydrates, or completely changed.

C Cow's Milk with Cereal additions. D. Combined Foods.