There are many excellent pasteurizers for home use on the market, but entirely satisfactory results may be obtained by improvising one from the wire bottle rack seen in Fig. 47, and the large kettle already provided. One method is to place the rack, containing the bottles, in the kettle which is filled with cold water to a level a little above the top of the milk in the bottles, and allow the water to come to the boiling point. The kettle is removed from the fire, covered tightly and the bottles allowed to stand in the hot water for twenty minutes. Cold water is then run into the kettle to cool the milk gradually and avoid breaking the bottles, after which they are placed in the refrigerator, well or spring-house and kept at a temperature of 50° F. until they are taken out, one at a time, for feedings. If a wire rack is not available the bottles may be stood on a saucer or a thick pad of folded newspapers in the bottom of the kettle. Pasteurization does not destroy all germs that may be in the milk, but it kills the more important ones and apparently impairs the nutritive and protective properties of the milk less than boiling. However, pasteurized milk must be kept cold and must be used within twenty-four hours, for the aging of milk is quite as undesirable as souring. Scalding is another method of destroying germs in milk. The milk is placed in an open vessel and the temperature raised to about 180° F., or until bubbles appear around the edge and the milk steams in the center, after which it is cooled and kept at a temperature of 50° F. Many doctors prefer to have the baby’s milk boiled, since boiling insures absolute sterilization and also renders the curd more digestible. Other changes are produced by boiling, however, which make it important to add orange juice and cod-liver oil to the baby’s diet at an early date, as will be explained in the next chapter. Milk may be boiled directly over the flame for a time varying from three to forty-five minutes, or it may be placed in a double boiler, the water in the lower receptacle being cold, and allowed to remain until the water has boiled from six to forty-five minutes. When milk is boiled or scalded, the other ingredients are added beforehand, as a rule, after which it is measured and poured into the bottles. Or the milk mixture may be poured into the bottles as for pasteurization and the bottles kept in the actively boiling water for any desired length of time. All of these points, however, are definitely specified by the doctor.