The author has been unable to verify the above measurements, and has, on the contrary, found no uniformity in the size of the stomach for given ages; still clinical experience is a sufficient guide, and upon this the following table is based:

Table Of Intervals Of Feeding And Average Amounts Of Food

c. The object to be accomplished in the preparation or modification of cows' milk is to make it resemble human milk as much as possible in chemical composition and physical properties. To do this it is necessary to reduce the proportion of proteids, to increase the proportion of sugar, and to overcome the tendency of the casein to coagulate into large, firm masses upon entering the stomach and coming in contact with the acid gastric juice.

Dilution with water is all that need be done to reduce the amount of proteids to the proper level; but as this diminishes the already insufficient sugar, and also the fat, it is essential to add these materials to the mixture of milk and water. Fat is best added in the form of gravity cream which contains approximately 16 per cent, of fat; and of the sugars, either pure white loaf sugar or sugar of milk of good quality may be used. The latter is greatly preferable, because it is the natural sugar, is directly assimilable, in the process of digestion is converted into lactic acid, and, unlike cane sugar, is not readily fermented. One ounce of milk sugar to twenty ounces of food properly proportioned for the first four months, gives a sugar percentage similar to human milk, i. e., 6 to 7 per cent. If cane sugar be used, one-half the quantity is required.

Firm clotting may be prevented by the addition of an alkali or a small quantity of some thickening substance or attenuant.

Lime-water is the alkali usually selected. It neutralizes the slightly acid reaction which usually characterizes market milk and has a further chemical action which is variously explained. Some authorities claim that to the extent of the quantity of lime-water added a soluble calcium caseinate is formed which is not acted upon by the acid gastric juice with the precipitation of firm curds. Others, that lime-water causes the mucoid proteids (Storch) of the milk to swell up and become viscid, thus tending to gelatinize the curd, and by its alkaline properties to retard the curdling action of the gastric secretion. Whichever theory is accepted the result is the same, the total bulk of casein coagulum is diminished and the ease of digestion increased. To produce measurable results the quantity of lime-water to be used must always be in the proportion of one part to twenty of milk mixture. When lime-water is constantly employed, it becomes quite an item of expense if procured from the chemist's. This outlay is unnecessary, for it can be made quite as well in the nursery. Take one heaping teaspoon-ful of slaked lime and put it with one quart of boiled or distilled water into a bottle, cork securely, and shake thoroughly two or three times, at intervals of half an hour; then allow to settle and after twenty-four hours siphon off for use the upper clear fluid; this must be kept in a well-stopped, perfectly clean bottle.

Instead of lime-water, bicarbonate of sodium may be added to each bottle in the proportion of one grain to each fluidounce of milk mixture; or, better still, from five to fifteen drops of the saccharated solution of lime. This solution is made in the following way:

Take of -

Slaked lime..........................

Refined sugar, in powder...............

Distilled water........................

1 ounce.

2 ounces. 1 pint.

Mix the lime and sugar by trituration in a mortar. Transfer the mixture to a bottle containing the water, and having closed this with a cork, shake it occasionally for a few hours. Finally, separate the clear solution with a siphon and keep it in a stoppered bottle.

Thickening substances, attenuants, are employed to act in the main mechanically by getting, as it were, between the particles of casein during coagulation, preventing their running together and forming a large compact mass. This class embraces gummy materials like dextrin, gelatin, the various infants' foods prepared by Liebig's process (in which the starch of wheat and barley is converted into maltose and dextrin), and finely divided starch as it exists in barley- or oatmeal-water; and it is for this purpose only that starch is permissible as an element of diet in infancy. Barley-water and gelatin* are the attenuants usually employed.

When an "infant's food" is used to act mechanic-ally, care should be taken to select a reliable one, that is, one in which the starch has been converted into maltose and dextrin by the process of manufacture. The articles known as Mellin's Food and Horlick's Food can be relied upon. One teaspoonful of either dissolved in a tablespoonful of hot water and added to each portion of food, makes a very easily digested mixture. Dry malt extracts also act well mechanically, being especially useful when desirable to reinforce the fat-building elements of the food.

* See Chapter IX (Dietary).

It must not be inferred from what has been stated in regard to the use of lime-water and attenuants that these are essentials in the artificial feeding of infants. On the contrary, the majority of healthy babies require Only sound cows' milk, properly modified by the addition of cream, milk sugar, and water. It is best to leave the addition of lime-water, bicarbonate of sodium, or an attenuant, to thejudgment of the physician.

For the successful management of children, the mother or nurse must not only be familiar with the theory of feeding, but must practically understand the methods of preparing food. To this end a schedule of the diet of an infant from birth upward, with a sketch of the modifications that have to be made most frequently, will serve as a useful guide.