ACIDITY
Like mother's milk, the cow's milk is neutral as it comes from the udder; but, on standing, it quickly changes, soon becoming slightly acid, as shown by testing with blue litmus paper. In fact, what is known as ordinarily fresh milk, if subjected to the litmus paper test, always gives an acid reaction. This acidity is neutralized by adding lime water to the formula in the proportion of one ounce to each twenty-ounce mixture. Ordinary baking soda is sometimes prescribed by physicians in place of the lime water. In the event of obstinate constipation, milk of magnesia is sometimes added to the day's feedings.