No. 4.] SOURING OF MILK. 253 



In conclusion, — milk, leaving the udder almost in a 

 spray, comes in contact with a large quantity of bacteria- 

 laden air. This milk is of a temperature most congenial to 

 bacterial growth, hence the first half hour of its life is the 

 critical one. The way it is treated during that time deter- 

 mines its keeping qualities, and to a considerable extent its 

 flavor. No wonder the best teachers say that sour milk is 

 due to careless handling. As a matter of theory milk cared 

 for as we have recommended will keep a long time, amply 

 sufiicient to have it reach any consumer in good condition, 

 and the following of these suggestions will add many hours 

 to its life. As a matter of practice many farmers take these 

 precautions and are never troubled with sour milk. A 

 German experimenter had a cow kept in a badly ventilated 

 barn and milked without having its udder cleaned, and the 

 milk, kept at 60°, coagulated in fifty hours. The milk from 

 the same cow drawn in an open field, after the hands of the 

 milker and the cow's udder had been cleansed, kept, at the 

 same temperature, eighty-eight hours. Hence we have both 

 theory and practice to back up these ideas. What one 

 farmer has done another can do. With proper precautions 

 there would ])e no renewal of the great trouble which annu- 

 ally exists in Boston and elsewhere during the "heated 

 term " on account of sour milk. 



