Principles of Milk Preservation. 



109 



continuous stream and is generally discharged in the 

 same way. The objection to this type of apparatus is 

 that the time of heating cannot be regulated with any 

 certainty, although the temperature can be controlled 



FIG. 24. Hochmuth's combined heater and cooler. Cold water enters at k and 

 circulates through coil, cooling the milk which is heated in upper part of ribbed 

 surface. This warm water is used to warm the milk, and then steam is intro- 

 duced through d. 



in part by varying the speed of flow. Another objection 

 is that the rapid heating often necessitated by these ma- 

 chines scalds the proteids of the milk, making them ad- 

 here to the walls of the pasteurizer. 



