194 DAIRY FARMING 



chiefly by the large amount of sugar present. The other 

 class is the unsweetened. Nothing is added to the milk. 

 The preservation depends upon heating the product after 

 it is in cans in a steam oven under pressure until it is 

 completely sterilized. Several grades of this class are made. 

 A condensed milk factory can only be operated where a large 

 supply of perfectly fresh milk can be obtained. The con- 

 densary is usually a good market for milk, but the farmer 

 supplying the milk has the same trouble raising his calves 

 as in the case where whole milk is sold in any other form. 



183. Milk Flour. A few factories make powdered milk, 

 or milk flour. For this a part of the fat is removed, and 

 the milk is dried to make a fine white powder that keeps 

 well. When water is added, the powder dissolves. 



QUESTIONS AND PROBLEMS 



1. Which is heavier, cream or skim-milk? 



2. What purpose does each of the constituents of milk serve 

 when used as food? Which is the most important constituent? 



3. Compare the amount of fat in Holstein milk with the amount 

 in Jersey milk when the latter is considered as 100 per cent. Com- 

 pare the protein in the same way. 



4. Why is the percentage of fat not an accurate measure of the 

 value of milk as food ? 



5. Is it possible to increase the percentage of fat in milk by 

 changing the feed ? 



6. Is the color of milk a sure indication of the percentage of 

 butter-fat contained ? 



7. Where does each constituent of the milk go when milk is 

 used for butter making ? For cheese making ? 



8. What reasons are there for stripping a cow ? 



9. What are the legal standards of your state for milk and 

 butter ? Some of this information is given on page 297. What are 

 the restrictions on the sale of oleomargarine ? 



10. What principle of physics is the basis for the operation of 

 the cream separator and of the Babcock milk test? 



