272 MAN'S IMPROVEMENT OF HIS ENVIRONMENT 



Conclusion. — What is the annual cost of typhoid, tuberculosis, 

 and diarrheal diseases of children to the city of New York ? 



Problem 243 : What are the chief causes of death in a city ? 

 Method and Observations. — From the foregoing table deter- 

 mine : 



(1) The relation of the number of deaths from infectious dis- 

 eases to the total death rate. 



(2) The diseases which kill the most children. 



(3) The per cent who actually die of old age. 



Conclusion. — 1. What percentage of all people of the city die 

 from old age? 



2. What diseases kill most babies and children under five years 

 of age ? 



3. What diseases in the list might be influenced by alcohol? 



Problem 244: : To study the relation of the death rate to the 

 season. 



Method. — Study tables carefully in the following manner: 

 Note a given disease, as typhoid, and make a graph, using figures 

 given, to determine the number of cases reported and number of 

 deaths monthly in New York city. 



Conclusion. — Is typhoid equally prevalent all the j'car round? 

 How do you account for its great prevalence in the faU? 



(The instructor should divide up the work so that each member 

 of the class will be responsible for a separate graph. A general 

 discussion may then be held on the relation of various diseases 

 to the city death rate. For example : What disease is responsible 

 for the greatest death rate ?) 



Problem 245 : To find a relation between flies and mortality. 



Method. — ^Refer to mortality tables published on pages 270, 

 271, and fill in the table on the opposite page. 



Observations. — With the aid of the given data, construct a 

 graph showing the prevalen-ce of flies and number of deaths per 

 month for the dates given. (In making curves on cross section 

 paper let 1 cm. = 50 deaths, and 1 cm. = 200 flies.) 



Conclusion. — 1. Is there any relation between the prevalence 

 of flies and the number of deaths from diarrhea? 



