BACTERIA. 161 



human system in very large quantities, but there is 

 so little of it on smoked meats that no harm what- 

 ever results. The smoke of most any kind of wood 

 will preserve meat, but some kinds give better 

 flavors than others. 



Sugar is also a preservative against the action of 

 germs. It is used to a limited extent in curing 

 meats, but very widely in the preservation of fruits. 

 Such fruits are cooked for a long time. The cook- 

 ing, or "boiling down," kills all germs present, and 

 drives off the water, thus making conditions unfit 

 for others to grow. Some dried fruits, such as figs, 

 dates, raisins, and currants owe their good keeping 

 qualities to the large amount of sugar present. 



RELATION OF BACTERIA TO DAIRY PRODUCTS. 



Milk, when freshly taken from the cow, contains 

 few, or no, bacteria. During the ordinary proces? 

 of milking, however, millions of germs find their 

 way into the milk. Bacteria are floating in great 

 numbers in the dust of barns. They are on the 

 hay, in the litter on the floor, on the hairs of the 

 cows and other animals, and in the clothing and on 

 the hands of the milker himself. 



Any hairs, dirt, or dust falling into the milk pail 

 carry with them large numbers of germs. There 

 is generally a great deal of dust in the cow stabl^ 

 at milking time. This is stirred up by the handling 

 of hay and other feed. Cows shed their hair more 

 or less all the time, and it is not uncommon for 



