Papers ox Medici>-e. Pr^Lic Health a>-d Saxitatiox S9 



* * * * The reported cases and deaths due to iufluenza 

 were collected for each county and from these data we 

 estimated the rate per 100,000 of population and the 

 deaths per 1,000 of cases. TVe found that the average 

 for the State was 3.517 cases and 396.6 deaths per 100,000 

 of population and the deaths were 112.7 per 1,000 cases. 

 Dividing reported cases and deaths each into three 

 classes we find nine possible combinations : — High mor- 

 tality and high morbidity, high mortality and medium 

 morbidity, high mortality and low morbidity, etc. 

 Upon coloring the map of the state according to 

 these nine classes we find the various colors are 

 pretty evenly distributed through the State. Xeither 

 north nor south, east nor west shows any special 

 color. Two counties, namely Pope and Schuyler, 

 were given a distinctive color because their reports 

 were manifestly unreliable. We do find that the populous 

 centers and the coal mining areas show a large amount 

 of the disease. The counties showing both high mortal- 

 ity and high morbidity are Lake, LaSalle, Grundy, Eock 

 Island, Peoria, Champaign, Christian, Franldin, Perry 

 and Union. Those showing low morbidity and low mor- 

 tality are Carroll. Lee, Kendall, DuPage, Putnam. Stark, 

 Cumberland, Clark. Clinton, Hamilton and Williamson. 



It is easy to see that where the population is close to- 

 gether the opportunities for infection are more numer- 

 ous ; also where people are closely associated the chance 

 is gTeater that the infective dose will be large. The in- 

 dications are that the germ of influenza is conveyed 

 through exhaled droplets. In crowded work rooms and 

 in mines the chance is great that the air may be saturated 

 "u-ith these germs if there be cases present. We are not 

 surprised, therefore, that in crowded sections the cases 

 should be numerous and severe, but Cook County, and 

 especially Chicago, shows less mortality than Lake, La- 

 Salle or Grundy, where the density of population is less. 

 There must be some other important factor. 



There are certain imj)ortant general biologic laws 

 which must be remembered, (a) "VThen a germ is im- 



