358 BOARD OF AGRICULTURE. [Pub. Doc. 



tors and coolers in use for this purpose are the Star and 

 Champion coolers. These simple contrivances can be found 

 at all dairy warehouses. The Champion has the advantage 

 of allowing a piece of ice to be placed in the water used in 

 the cooler, and but very little water is actually needed. In 

 case of the Star cooler, a current of water must constantly 

 run through the cooler to secure the best results. Milk as 

 it comes from the cooler is drawn into cans or other vessels, 

 and still further cooled by being immersed in vessels contain- 

 ing ice water as near the temperature of 38° F. as possible, 

 and held there till marketed. 



It wall thus be seen that the secret of having clean, pure 

 milk consists in keeping out all of the bacteria possible, by 

 observing the most rigid rules of cleanliness, and in prevent- 

 ing those that unavoidably gain access, from becoming ac- 

 tive, by holding the milk at as low a temperature as possible. 

 Bacteria being plants, it is impossible for them to grow when 

 the temperature is within six or eight degrees of freezing. 



Cream. 

 Cream may be defined as that portion of the milk in which 

 has been gathered the largest proportion of fat. It is com- 

 posed of the same substances found in the milk, but these 

 substances do not exist in the same relative proportions. 

 Cream separates naturally from the milk because of the dif- 

 ference in specific gravity between the globules of fat and 

 the remainder of the milk (milk serum). If milk is allowed 

 to remain at rest in a vessel, the fat globules, being lighter 

 than the other ingredients, rise to the surface of the liquid. 

 In so rising they carry with them a portion of the other 

 materials of the milk, and the mixture is called cream. 

 While the composition of the cream varies, especially in its 

 fat content, depending upon the method of separation, the 

 following figures give an idea of an average sample of Cooley 

 cream : — 



Cream. Per Cent. 



Water, 72.90 



Fat, 18.00 



Albuminoids, 3.90 



Milk sugar, 4.50 



Ash 69 



