24 DUST AND ITS DANGERS. 



York, at a place as far from the streets as pos- 

 sible, and about 25 feet from the ground, showed 

 the number of bacteria in 10 litres to be 56 and 

 of moulds 4. 



Analyses, during the same period, of the air 

 of the streets in New York, from various parts 

 of the town, 1 showed the average number of 

 bacteria in 10 litres to be 376, and of moulds 

 6. These analyses of street air were made 

 under ordinary conditions, at such times of the 

 day as the air appeared to be at its best. 



If an analysis is made of the air in the dust 

 clouds which sweep along the ill-kept streets 

 of a city like New York or which blows from 

 the street sweepers as they pass along the 

 unwatered thoroughfares into the houses or 

 over the unwary passer-by, the numbers of 

 germs to the litre is startling. 



Let us look at a graphic record of the rela- 

 tive number of bacteria in various places, made 

 by the plate method already described. 



Plate III. shows the result of a series of 

 comparative analyses made in this way in var- 



1 This was at a time when the so-called politicians were juggling 

 with the Street Cleaning Department while the streets were largely 

 left to take care of themselves. 



