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 When whey is boiled down to a thick syrup and left to stand, the sugar will crystallize out and may be separated from the liquid, still holding in solution the mineral matters.

Cream

Whole milk

Skim milk

Fat globules as they appear under the microscope

Mineral Matters.—These may be gathered as ash by boiling off the water from this liquid or from the whole milk and burning the rest, as all the constituents except the ash belong to what in chemistry is called organic matter, which disappears in the air by burning.

HOW TO TEST MILK

Dr. S. M. Babcock of Madison, Wis.

Milk may be adulterated or decreased in value either by skimming or by watering. In either case the percentage of the most valuable constituent, the butter-fat, is diminished. It is upon this fact that the most practical test, the Babcock, is based.