10:4::20:X. X = 80/10. X = 8.
Eight ounces would then be the amount of milk required for preparing twenty ounces of modified milk for an infant of this age.
In preparing modified milk according to the formulas just given, it must be remembered that in all instances only that portion is to be used which collects in the upper third of a bottle of milk that has been allowed to sit undisturbed in a refrigerator for at least four hours. The lime-water is for the purpose of correcting the acidity of the milk.
It is of much importance to select the milk from a healthy cow in all instances where it is to be fed to infants, and where possible, it should be examined by a competent laboratory man in order to determine if it answers the proper requirements. The writer has often seen milk from apparently healthy cows, which seemed in every way good, that showed on microscopic examination pus cells and a harmful germ (streptococcus).
It is not desirable to have a milk for this purpose that is too rich in fats, and for this reason a cow of the ordinary mixed breed is more satisfactory than the blooded Jerseys or Alderneys.
Not only is it essential to get the proper kind of milk, but the utmost care is necessary in handling it. It should, of course, be as free as possible from every source of contamination, and should be strained thoroughly as soon as milked. It should then be bottled, and chilled at once by being placed in cold water, and after being properly sealed, should be placed in a refrigerator at a temperature of about 50°F., where it should remain undisturbed for four hours before the top portion is skimmed off for making the modified milk.
After the modified milk has been prepared it should be returned to the refrigerator, where it should be kept until required for feeding. It is best not to use milk that has been in the refrigerator longer than twenty-four hours, or at most forty-eight hours, and then only if kept at a proper temperature. The modified milk should be poured directly from the receptacle in which it is kept into the feeding-bottle, and the latter should then be placed in warm water until its content is milk-warm, at which time it is ready to be given to the child.
It is highly necessary in feeding infants by the bottle to remember that cleanliness in everything connected with the process only makes success possible, and in no particular does this apply with greater force than in connection with the proper care of the bottle and nipple. In every case immediately after use they should both be put in water, which should then be brought to a boiling temperature, and both should then be kept in a saturated solution of boric acid. The nipple, after being placed on the bottle, should not come in contact with anything but the infant's mouth. Bottles that have no neck are much to be preferred to others, as they can be readily cleansed. There is on the market at the present time a bottle called the “Hygeia,” which possesses the necessary qualifications in a perfectly satisfactory way.
When children who have nursed at the mother's breast reach the age of weaning it is of importance to remember that they cannot eat without digestive disturbances the modified cow's milk of a strength that would otherwise correspond to their age; they should invariably under such circumstances begin with a milk prepared by the formula used for a child several months younger, after which the proportion of milk may be gradually increased until it is used in a pure state.
During very warm weather it is well to reduce the amount of fat by using the whole milk instead of the top portions, as heretofore described. The same precaution should be followed where children have acute diseases, and the total quantity taken should be less than under ordinary circumstances. Where infants have acute indigestion, accompanied by vomiting and diarrhœa, all milk should be for the time withheld,—boiled water being substituted; some hours later barley water may be given, but no milk for at least twenty-four hours. Where children have loss of appetite, it is well to give less cream, and the intervals between food should be increased.