382 SCIENCE OF HOME AND COMMUNITY 



ization may be done in this simple way. (See figure 146.) 

 A pail is partly filled with boiling water, and in this are 

 placed the bottles of milk. The water should come nearly 

 to the tops of the bottles. The bottles are allowed to remain 

 here about a half hour and the milk should be stirred occa- 

 sionally. The boiling water is cooled by the milk, and the 

 amounts of water and milk can be so regulated that the 

 final temperature of milk and water will be about the 160 

 degrees desired. When the milk has been heated enough, 

 it should be cooled quickly. This may be done by allowing 

 cold water to run into the pail. Inexpensive pasteurizing 

 outfits may be bought in the market. 



DEMONSTRATION 31 



Purpose. To try the effect of pasteurization on the keeping 

 quality of milk. 



Materials. Beaker, test tubes, thermometers. 



Directions. Fill the beaker half full of water, and the test 

 tube half full of milk. Put the test tube in the beaker. Heat 

 the beaker and put the thermometer in the water. Regulate 

 the flame so as to keep the temperature between 160 and 170 

 degrees for about a half hour. Take out the tube and plug 

 the mouth with cotton batting. Fill another tube half full of 

 milk and plug with cotton. Allow the two tubes to stand side 

 by side for several days and notice how long the milk in each 

 keeps sweet. 



Food. Three common ways in which typhoid fever germs 

 may be carried have been explained, namely by water, milk, 

 and flies. In addition to these means the germs may some- 

 times be carried in various articles of food, as on uncooked 

 fruits and vegetables and on raw oysters. Epidemics of 

 typhoid have occurred from eating uncooked oysters, which, 

 it was later found, had been fattened in a bay into which 

 had emptied the sewage from a house containing a typhoid 

 patient. A wise precaution in the use of fruits and vegeta- 



