Total Solids.' 

 /o 



Holstein,' 12.00 



Ayrshire, 12.50 



Shorthorn, 12.90 



Devon,'' 13 -4° 



Jersey, i4-7o 



Guernsey, i4-7o 



While the alcove figures may be taken as types, they do not mean 

 that every cow of a distinct breed will yield milk of the above com- 

 position. In fact, many Jerseys produce milk with no more than 

 4.50 per cent, fat, while individuals of the Holstein breed frequently 

 yield milk as rich as do Ayrshires, or even some Jerseys. 



Pure milk may be defined as the natural 

 Pure and Impure product of a healthy cow, drawn and cared for 

 Milk. in a cleanly manner. Milk from diseased cows 



or from animals in a low physical condition 

 cannot be considered suitable for human consumption. Milk may 

 become tainted fiom dead skin and particles of manure that fall into 

 the pail during milking, from stable dust, from improperly cleaned 

 milk utensils, from dirty milkers and from bad odors. All forms of 

 material referred to as dirt are full of germ life, or bacteria. Under 

 the microscope bacteria exhibit a variety of forms ; many have been 

 classified, as have the higher plants, into families, genera, species 

 and varieties. Some forms have not as yet been studied and classi- 

 fied. Bacteria live upon and decompose vegetable and animal 

 matter. Warmth and moisture are quite necessary for their 

 rapid multiplication. Warm milk forms a very favorable medium 

 for the growth of bacteria, which having once gained access, in- 

 crease with wonderful rapidity, producing numerous changes which 

 will be explained and discussed in Part III of this bulletin. 



Milk is not a beverage, but an easily digest- 

 Food Value of ed, perfect food. 



Milk. The casein and allied substances (proteid 



bodies) furnish the body material for building 

 and repairs, and also serve as a source of energy. 



The fat and sugar serve as sources of heat and energy, while the 

 mineral matter aids in the formation of the various body tissues. 



' Includes all ingredients excepting water. 



- Includes all ingredients excepting water and fat. 



3 Koeniar. 



