A NEW YORK EXPERIMENT 265 



amount of dian'hoeal disease in the protected area. In the protected area there 

 were, in children under five years of age, twenty cases of diarrhoeal disease, and 

 fifty-seven cases in the unprotected or filthy area. In the former the duration of 

 the disease was 273 days, in the latter the total days of sickness were 984. Of the 

 other suggestive statistics contained in this rei)ort the following may be mentioned. 

 A bacterial count of the flies was made. The average number of bacteria on an 

 agar culture from flies in the clean area was 13,986 and in the dirty area 1,106,017. 

 The average number per fly of bacteria on Conradi plates (indicating intestinal 

 organisms) was 4489 on flies from the clean area and 292,117 from flies from the 

 dirty area. 



