16 Introduction. 



saturation be reached, simply because the rapidity of mo- 

 lecular motion increases with the temperature, for when 

 the molecules of foul odor are once inside the warm milk 

 they travel or diffuse downward more rapidly because it 

 is warm. 



15. Odors and Flavors Resulting From the Introduction of 

 Solids Into Milk. It must be clear from what was demon- 

 strated in (6) that when great care is not taken both in 

 keeping the stable and cows clean and free from dust the 

 fine particles of dirt falling into the milk, even though 

 the amount is small, may readily dissolve an-d impart a 

 strong flavor to it, and one careless milker may easily 

 greatly injure the quality of that from the whole herd 

 where all of the milk is pooled. The fundamental point to 

 be kept ever in mind is that a very little dirt is capable 

 of being divided to an extreme degree and that through 

 the senses of taste and smell extremely small amounts may 

 readily be detected. 



16. Odors and Flavors Developed in Milk After It is 

 Drawn. Milk is a very nutritive fluid and for this rea- 

 son great care must be exercised not only to keep dirt out 

 but also to prevent those germs from entering it which 

 have the power of developing rapidly there, producing un- 

 desirable odors and flavors and thus injuring the quality 

 of the milk. These objectionable germs are liable to be 

 introduced into the milk through the dust from the sta- 

 ble and the cow as well as from the lack of proper cleanli- 

 ness of the vessels in .which the milk is handled. 



17. Deodorizing Milk. The removal of odors from milk 

 may be accomplished by greatly increasing its surface in 

 a space containing none of the odors which the milk con- 

 tains. The method known as the "Aeration of Milk" has 

 for its purpose this rather than the exposure of the milk 

 to the air, as the presence of the air hinders the escape of 



