110 



Dairy Bacteriology. 



In some of these machines (Thiel, Kuehne, Lawrence, 

 De Laval, and Hochmuth), a ribbed surface is employed 

 over which the milk flows, while the opposite surface is 

 heated with hot water or steam. Monrad, Lefeldt and 

 Lentsch, employ a centrifugal apparatus in which a thin 

 layer of milk is heated in a revolving drum. 



FIG. 25. Monrad's centrifugal pasteurizer. Milk is introduced into center 

 through^, and is thrown out on the walls of centrifuge d, the steam being ap- 

 plied to the outside of the revolving drum. Reservoir m catches and holds the 

 milk for a moment. Milk finally flows at h. 



Some of these machines are suitable for heaters, if the 

 milk was held in vats that would retain the temperature 

 at a pasteurizing point for a sufficient length of time. 



Other machines of the continuous flow type employ a 



