Page:The story of milk.djvu/161

 ulated by heat and, with whatever butter-fat there may be left in the whey, skimmed off the top. In Norway Myseost ("Ost" is Norwegian for cheese) is made by boiling down whey almost to dryness. If goat milk is available to mix in, it improves the cheese. The main substance is sugar of milk and the cheese has a sweet, syrupy flavor.

The by-product, sugar of milk, is produced by acidifying the whey, heating to boiling and neutralizing with lime until the albumin is coagulated. It is then filtered out and the clarified liquid is concentrated in vacuum. From the thick syrup the sugar is allowed to crystallize out, leaving the salts or mineral matters (milk-ash) in the remaining liquid. The use of milk-sugar is limited to medicinal purposes and for modifying milk for infants. The production is therefore not very extensive.

In a number of creameries casein is produced from skim milk by precipitating it with an acid and drying and pulverizing the precipitate. Casein is widely used as a substitute for ivory, in billiard balls, buttons, etc. It is also used as glue, and as a binder in paints.