APPENDIX 153 



the characteristics of the principal fats of butter. 69. Why 

 does butter differ in composition from all other fats ? 70. What 

 is meant by the glycerine and fatty acid content of fats? 

 71. What is meant by saponification of fats ? 72. What are 

 the volatile fatty acids of butter? 73. Why do butters pro- 

 duced from different creams vary in hardness and other physi- 

 cal properties ? 



CHAPTER IV 



74. What is the lactometer and for what is it used ? 75. 

 What are the lactometer degrees? 76. How is the specific 

 gravity of milk determined? 77. Why does milk have a 

 higher specific gravity than water? 78. What influence 

 does the removal of the fat have upon the specific gravity of 

 milk? 79. What influence does the addition of water have 

 upon the specific gravity of milk? 80. To what extent do 

 changes of temperature influence the lactometer readings? 

 81. How is skimming or watering of milk detected? 82. How 

 can the Babcock test and the lactometer be used jointly in 

 milk testing? 83. How are the milk solids calculated from 

 the fat content and the specific gravity ? 84. How would you 

 determine the extent to which milks have been either watered 

 or skimmed ? 



CHAPTER V 



85. Give the physical properties of milk sugar. 86. What 

 changes does milk sugar undergo when milk sours ? 87. What 

 is produced? 88. Name the conditions necessary for fermen- 

 tation of milk. 89. What causes the fermentation to take 

 place? 90. To what extent may lactic acid form in milk? 

 91. What causes milk to sour and curdle? 92. How can the 

 amount of lactic acid in milk be determined? 93. Describe 

 the test employed for obtaining the acidity of rnilk. 94. How 

 is the amount of acid in the milk calculated? 95. Of what 

 value is this test in butter making ? 96. What per cent of 

 acidity should well-ripened cream show ? 



