242 



THE BIOLOGY OF DISEASE 



Sanitary measures are adopted to keep the sources of 

 the water from becoming impure, as well as to keep clean 

 the reservoir where it is stored. Certain harmless plants 

 and animals living in reservoirs may give an unpleasant 

 taste or odor to the water. Harmful disease germs live 

 in water for months. Such germs may be frozen in ice, 

 stored in ice houses, and when later put with the ice into 

 drinking water, may cause typhoid fever. It is, therefore, 



important that we have 

 plenty of pure water, and 

 we should do all we can 

 to help in giving the 

 town or city in which we 

 live a pure water supply. 



Introduction of 

 Antitoxin Treatment 



STUDENT REPORT 



Prepare a report on the water 

 supply in your locality and find 

 where it comes from. What 

 measures are taken to keep the 

 sources and reservoir clean ? 



184. Keeping Well. — 

 Our best doctors are 

 spending much effort in 

 showing how to avoid 

 disease, for no one is 

 benefited by illness. The 

 old notion that children should be exposed to measles, 

 scarlet fever, and whooping cough is wrong, for none of 

 these childhood diseases is necessary. The time will come 

 when our homes and surroundings will be so sanitary 

 that the common diseases caused by germs will be elimi- 

 nated, or at least decreased in number. 



Government inspection of meats is lessening the amount 



1881 87 89 91 93 '95 '97 1900 02 04 06 08 10 12 14 



Figure 244. — Diagram. 



Thirty years of diphtheria in New 

 York State. 



