A cow shut up in a stall, and poorly fed, will give a milk greatly deficient in solid constituents, and very liable to become sour.
Cows kept in the city, and fed on carrots, garbage, etc., will give a very inferior milk. It is therefore preferable to obtain milk from a cow that is at pasture, or that you are sure is fed on hay, straw, clover, or such forage as horses feed upon. Whenever it is apprehended that the milk may have an acid re-action, it should be tested with litmus- paper, and, if found so, a little lime-water may be added to render it slightly alkaline.
Great caution must be exercised in the selection of a person well known for honesty and integrity to supply the milk; for an ignorant and careless person may think it but a light trick to give you the milk of one cow instead of another: this little trick, however, may cost your child's life.
Engage the milk of one cow, which has just calved, and keep taking it from her until you have good reasons for changing. Examine the milk every time you receive it; do not trust ignorant servants or nurses; see to it yourself, and the milkman will conclude that you are in earnest in this matter, and will not attempt deception.
New milk should be brought morning and evening; for it will not keep sweet twenty-four hours without chemical means, which should not be allowed.
Many nurses heat the milk to the boiling-point as soon as they receive it, and keep in a cool place, in an open vessel. This treatment will prevent its turning in a few hours, even in a warm day.
A thunder-storm will turn the milk: this electrical influence gives the milk an acid re-action, and renders it unfit for use.
