110 THE STORY OF TffE BACTERIA. 



and lungs with the air out-of-doors, especially in 

 large cities, is, as we have already seen, imminent 

 and widespread, but ordinarily the dilution of 

 the dangerous elements is so great as to reduce 

 greatly the chances of evil effects from swal- 

 lowing or inhaling them. But still, in large 

 towns, whose streets are not faithfully cared 

 for, the probability of being obliged to pass 

 through clouds of dust whenever one goes 

 upon the streets, especially in the windy sea- 

 sons, is very unpleasantly suggestive of dan- 

 ger, and more than suggestive of filth. 



In New York, even in districts where the 

 streets are measurably frequently attended to, 

 the insufficient watering of the pavements be- 

 fore the street-sweepers pass, the long periods 

 which often elapse before the dirt heaps are 

 carted off, and the reckless way in which the 

 dirt is shovelled into the carts, are all evi- 

 dences of carelessness which greatly increases 

 the risk of street infection, and abuses which 

 ought to be at once corrected. 



But, after all, it is in living-rooms and in 

 places of assembly that we must look for the 

 most frequent sources of danger. While, as 



