276 MAN'S IMPROVEMENT OF HIS ENVIRONMENT 



c. How to keep Germs from Entering the Body of a Well Person 



Method and Observations. — Notice conditions existing in 

 crowded cities with reference to the number of flies and the relative 

 number of screens over food exposed for sale, etc. Note the con- 

 dition of the streets and sidewalks, locate saloons or other places 

 where spittoons are found. Find any other places where you think 

 germs might exist and from which they might be carried by flies 

 or other insects. What household insects might be disease 

 carriers ? (See Civic Biology, pages 225-227.) 



Do you find any public drinking fountains? Any common 

 towels? Common combs and brushes? 



Also inquire into the condition of your local water supply. Is 

 it pure at the source? Does the supply come from a river? If 

 so, are there any towns or hamlets that empty their sewage into it ? 

 What danger might come from this ? Is your city doing anything 

 to eliminate this danger? What might your city do to prevent 

 it? What can you do to prevent disease from this source? 



What is the condition of your milk supply ? Does your board of 

 health do anything to protect the milk supply ? If so, then what 

 does it do? Are several grades of milk sold? Is dipped milk 

 sold ? If so, for what purposes ? How can you protect yourself ? 



What is the condition of the disposal of sewage in your city? 

 Does the sewage reach a river near by untreated, or is the sewage 

 treated before it escapes? Look up some book of reference in 

 this chapter on sewage disposal, and make a report to the class 

 on some of the methods of sewage disposal. Visit a municipal 

 museum, if possible, and report on various methods of sewage 

 disposal as shown in the sanitation exhibit there. 



Conclusion. — Write up a short composition for your notebook, 

 showing all the public and private means that should be taken to 

 prevent germs from entering the body of a well person. 



d. How to develop Immunity in the Body of a Well Person 



Method and Observations. — Read in your Civic Biology and 

 other reference books as to what immunity is and how it is brought 

 about. 



