146 PRACTICAL DAIRY BACTERIOLOGY 



of the dairy repeated, and the same precautions are necessary. 

 Cleanliness and sterilization must be the watchwords. The 

 use of glass jars is a very great improvement over the older 



FIG. 55 RESULTS OF THE ROUGH USAGE ON THE RAILROAD 

 It is almost impossible to clean the can on the left 



method of delivering from cans, chiefly because they are sure 

 to be cleaner. They are smooth so that they are easily washed 

 and transparent so that dirt is quite sure to show. Then, too, 

 after they are once filled and covered with their caps they are 

 quite well protected from external contamination on their jour- 

 ney from the factory to the consumer. All of this contributes 

 to the purity of the milk. Of course, all glass bottles must be 

 thoroughly washed and sterilized. 



