During the latter three or four months of the first year, the milk should be strengthened by some farinaceous food. Most of the proprietary infant foods can now be used with advantage, and are a useful means of adding sugar and starch to the food and of lending variety to the diet (see p. 154).

Carbohydrate can, however, be usefully added to the diet in another form. The infant has reached an age at which he demands something to chew, and also at which the eruption of teeth and the development of the jaws is in active process.

A crust of stale bread is now a valuable part of the diet, and it is well to spread this crust freely with butter. Other than milk, which still forms the bulk of the diet, and occasionally a portion of a raw egg, animal food is not advisable at this time.

During the second year, however, animal food in the form of soup, gravy, fish, and minced meat comes to occupy a large and important place in the dietary. Such food is rich in protein, and is a valuable means of securing healthy development.

Carbohydrates at this period, as in later life, are readily digested and readily absorbed. For these reasons it is obvious that carbohydrate is a very valuable form of foodstuff in childhood. But carbohydrate is apt to be given in excess at this time, and sooner or later bacterial fermentation sets in, with its resulting gastro-intcstinal symptoms.

Fat is still an important element in the diet, and is usually readily digested in the form of cream or butter. Cream, butter, and eggs are valuable forms of nourishment for the child, and care must be taken that their place is not usurped to any extent by increase in the amount of carbohydrate. But, on the other hand, excess of fat in the food is also associated with danger, and is intimately connected with the extremely complex subject of"acidosis" in children. The exact explanation of this condition is unknown. It is invariably associated with the presence of acetone in the urine, and minor degrees of this condition of acetonuria are extremely common.

Owing to the vomiting which accompanies the serious acute condition of acidosis, it is frequently impossible to give the child anything by the stomach. If solution of sodium bicarbonate (15 grains, hourly, for six hours) is not retained, the stomach must be washed out, normal saline solution injected subcutaneously, and attempts made to inject the alkaline solution intravenously if it is still rejected by the stomach.

In the minor cases of acetonuria a purgative should be administered, the diet restricted to milk diluted according to the age and general condition of the child, and alkalis given freely.

With the resumption of a fuller diet, care must be taken to sec that the various food constituents occur in their right proportions.

On the other hand, the importance of a sufficiency of fat in the food has been frequently alluded to, and will be considered more particularly later, in connection with the subject of rickets.

In any ordinary diet salts are present in abundance, and during the first two years of life it is important that they should be obtained from milk, which is rich in three of the substances most necessary at this period - calcium, potassium, and phosphorus. Some of the more important sources of iron are vegetable substances, such as oatmeal, also meat and eggs.

Most healthy children eat more than is absolutely necessary for their bodily requirements, and a small surplus amount of food in general cannot be regarded as other than good for the child. Habitual under-feeding is undoubtedly markedly injurious.