FROM THE PRACTICAL VIEWPOINT 



Instances have been known where the drivers of 

 rival companies have opened the bottles belonging 

 to their competitors, and have fouled the milk in 

 order to cast discredit upon the milk delivered by 

 the rival concern. Other drivers have taken cream 

 from the tops of bottles, and have filled the bot- 

 tles with water. The cream they have sold for 

 their own profit. Bottles which were effectively 

 sealed could not be treated in this way. 



Second : To prevent possible contamination of the 

 milk by means which are unintentional. The use of 

 the usual paper plug cap leaves a space above the 

 cap where dust and dirt and ice water from melt- 

 ing ice, etc., can collect. Unless this is carefully 

 washed off before the bottle is opened, it is likely 

 to fall into the milk. If a bottle of milk which 

 when filled has a temperature of say 50 to 55 

 is then placed in a case and covered with ice, the 

 milk is cooled to perhaps 35 to 40. This causes 

 the milk to contract. The air in the space above 

 the milk also contracts, and a suction is thus cre- 

 ated. The water which collects on the top of the 

 cap is then drawn into the bottle around the edge 

 of the cap, taking with it some of the dirt which 

 may have collected there. 



179 



