I. In using modifications made from top-milk, much confusion arises from the notion that top-milk is a single definite thing, whereas its composition depends upon a great variety of conditions and, unless all these are known, it is impossible to tell how strong it is. Directions for the removal of top-milk should be explicitly followed (see page 63), or the results will be very different from those expected. II. In formulas calling for a certain number of ounces of top-milk of any given strength, the mistake is made of removing only the number of ounces needed for the formula. The proper way is to remove the amount required to secure a top-milk of the desired strength and then to take of this the number of ounces needed in the formula. III. A rich Jersey milk is used as if it were ordinary milk. The formulas given in this book are chiefly calculated on the basis of a good average milk which contains about 4 per cent fat. Many persons have the idea that the richer the milk, the more rapidly the child will gain in weight, and hence the superiority of such milk for infant feeding. While it is true that some children taking a very rich milk may, for a time, gain rapidly in weight, yet sooner or later, serious disturbances of digestion are nearly always produced. IV. The food is increased too rapidly, particularly after some disturbance of digestion. If, in an infant three or four months old, an attack of somewhat acute indigestion occurs, the food should seldom be given in full strength before two weeks. The increase in the diet should be made very gradually, the steps being made only one half those indicated in the series of formulas on pages 70 and 71. Otherwise it generally happens that the attack of indigestion is very much prolonged and much loss in weight occurs. V. When symptoms of indigestion occur, the food is not reduced rapidly enough. Indigestion usually means that the organs are, for the time, unequal to the work imposed. If the food is immediately reduced by one half, the organs of digestion soon regain their power and the disturbance is short. In every case the amount of reduction should depend upon the degree of the disturbance. PREPARATION OF COW'S MILK AT HOME _What articles are required for the preparation of cow's milk at home?_ Feeding-bottles, rubber nipples, an eight-ounce graduated measuring glass, a glass or agate funnel, bottle brush, cotton, alcohol lamp or, better, a Bunsen gas burner, a tall quart cup for warming bottles of milk, a pitcher for mixing the food, a wide-mouth bottle for boric acid and one for bicarbonate of soda, and a pasteurizer. Later, a double boiler for cooking cereals will be needed. _What bottles are to be preferred?_