92 ILLINOIS ACADEMY OF SCIENCE 



few double reports would be very misleading as each case 

 would be at the rate of 100 per'^100,000. 



Comparing a map showing density of population of 

 counties with the influenza map we see that density of 

 population has apparently little direct relationship either 

 Avith the incidence or fatality of influenza. Of the coun- 

 ties shoAving high incidence and high mortality only three 

 have a population of over 90 to the square mile accord- 

 ing to the 1910 census, namely, Lake, Rock Island and 

 Peoria. Williamson County is high in population but 

 low both in incidence and mortality from influenza. The 

 mortality in Cook County from Influenza is medium, and 

 there the population is most dense. The same is true of 

 Madison and St. Clair Counties, Avhich are also reckoned 

 among the dense population. Carroll, Lee, Kendall, 

 Stark, Putnam, Clark, Clinton and Hamilton Counties 

 which are Ioav both in incidence and mortality from in- 

 fluenza haA^e a population of less than 45 to the square 

 mile. Generally speaking the counties having a popula- 

 tion less than 45 to the square mile show low mortality. 



On looking oA^er the death certificates one is struck with 

 the large number of names AA^hich shoAv Italian, or Slav 

 nationality. This class of people generally liA^e in croAA^ded 

 quarters Avliieh are poorly A^entilated. We are lead to 

 suspect that their great mortality is not due to their na- 

 tionality per se but it is more likely to be the result of 

 their enA'ironment and manner of liAing. This predomi- 

 nance of such foreign born among the deaths in mining 

 communities may perhaps to some degree account for the 

 increased mortality among miners. A special study was 

 not made upon this point, but the suggestion is made 

 more from a general knowledge of conditions. 



STATE OF ILLINOIS 



DEPARTMENT OF PUBLIC HEALTH 



JANUARY, 1920 



INFLUENZA, Illinois, Fiscal Year, July 1, 1918-June 30, 1919 



Popula- 

 tion 



STATE 6,359,102 



Adams 64,588 



Alexander 25,699 



Bond 17,949 



Boone 15,481 



