52 BUTTER-MAKING. 



results cannot be obtained unless extreme precautions are 

 taken. Milk produced under average farm conditions sel- 

 dom contains less than 50,000 germs per c.c. shortly after the 

 milking. Milk which is produced under filthy conditions, 

 and which is several hours old, may contain several millions 

 of bacteria per c.c. 



Sources of Bacteria in Milk. — Except in the cow's udder 

 where they are present to only a small extent, bacteria are 

 present almost everywhere. They float in the atmosphere 



Fig. 11. — The wrong and the right kind of a milk-pail, a, the ordinary- 

 type of pail showing sharp angle between sides and bottom; B, the same 

 properly flushed with solder so as to facilitate thorough cleaning. The 

 lower figure represents a joint as ordinarily made in tinware. The de- 

 pression a affords a place of refuge for bacteria from which they are 

 not readily dislodged. This open joint should be filled completely with 

 solder. (From Bui. 62, Wis.) 



and adhere to particles of dust. Especially is this so in the 

 dusty cow-stable. They are present in all well water to a greater 

 or less extent. They are very abundant in streams and rivers. 

 They are present in the soil to a depth of several feet, the 

 number decreasing with the depth. As these germs are prac- 

 tically present everywhere, the source of germs in milk may 

 be said to be all around us. The principal sources of germs 

 in milk are, however, unclean dairy utensils, unclean cows, 

 and unclean surroundings. As these germs multiply chiefly 

 by fission, or by one cell dividing into two, it is plain that the 

 number of germs will increase very rapidly under favorable 

 conditions. Under the most favorable conditions it requires 



