How to Keep Well 469 



of health enforce laws that will insure the delivery of milk of 

 approved quality. 



Pasteurization. Pasteurization is the process by which 

 harmful bacteria in milk are destroyed by heating, without 

 changing its taste or injuring its nutritive value and its digesti- 

 bility. It is named after Pasteur, a great French chemist, who 

 invented the process. Pasteurization is accomplished by heating 

 the milk to a temperature not over 170 Fahrenheit for about 

 twenty minutes. Milk to be used by infants should always be 

 pasteurized. In sections where pasteurization has been practiced, 

 there has invariably been a decrease in sickness and deaths from 

 intestinal diseases which are caused by germs. 



Experiment to Show the Nature and Effects of Pasteuriza- 

 tion. Put a half-pint of fresh, raw milk into a pint bottle. In 

 a beaker pasteurize a half-pint of the same quality of milk by 

 heating it to 160 degrees for 15 minutes. Put the pasteurized 

 milk into a pint bottle. Set both bottles aside in a cold place for 

 24 hours. Mount a drop from each bottle on a glass slide. 

 Examine them under the microscope. What is the difference 

 in the milk from the two bottles? What do you conclude about 

 pasteurization ? 



Other Food Supplies. Large cities have public markets 

 where poultry, fresh vegetables direct from gardens, and foods 

 of many kinds may be bought each day. Great care should be 

 taken to make sure that all articles of food are free from germs 

 of disease. Some cities have a food inspection division under 

 the direction of the Board of Health, whose duties include inspec- 

 tion of food of every kind. 



Sewage. The disposal of waste is one of the great sanitary 

 problems of every large community. Unless removed far from 

 its source, or purified by some chemical process, it becomes a 

 breeding place for germs of disease, as well as an unpleasant 

 factor in the neighborhood. The method for sewage disposal 

 best adapted to a given locality can be determined only by a 

 careful consideration of all the factors and conditions involved. 



Proper Clothing. The wearing of clean clothes of the right 

 kind is important to one's health. Wool, because it is loosely 



