Clean Milk 



and tuberculosis, it will be admitted that it 

 is a factor deserving attention. 



By the ordinary observer impure milk is 

 recognized by its containing coarse dirt, hair, 

 etc., which settles at the bottom of the can 

 or bottle, also by its sour taste or its curdling 

 when heated, and by its emitting the odor of 

 decomposition. But the absence of all of 

 these by no means indicates that the milk is 

 pure or safe. Milk may be entirely unfit for 

 food when none of these conditions are pres- 

 ent, since the chief dangers in milk are due 

 to the bacteria which it contains, and bac- 

 teria are far too small to be seen by the 

 unaided eye, being among the smallest and 

 simplest of all living things. They much 

 resemble the cells of which plants are com- 

 posed, and require moisture, warmth, and 

 food to grow. Milk is the only article of food 

 in which nearly all bacteria grow rapidly, 

 and in it they multiply at a favorable temper- 

 ature, %. e., about blood heat, in an almost 

 incredible manner. From a single germ as 

 many as 200 may be produced in three hours; 



12 



Digitized by Microsoft® 



