WHAT WE BREATHE 



FEW people realise that, with the advent of 

 autumn, the great majority of the swarms 

 of bacteria which have been circulating in the air 

 during the hot summer months take their leave of 

 us and disappear. 



Practically, however, we are all conscious of this 

 fact, for we know what greater difficulties attend 

 the keeping of food sweet and wholesome in the 

 summer than are met with in the winter ; bacteria, 

 not unlike some other armies of occupation, 

 securing a footing rather by their numbers at this 

 season of the year, than by virtue of the superior 

 strategy or, in other words, special attributes of 

 their units. Bacterial operations are, however, 

 distinctly favoured by the accident of temperature, 

 the warmth of the summer encouraging their 

 .vitality and multiplication. 



When Pasteur first announced his conviction 

 that the familiar phenomena of putrefaction and 

 decay were due to minute living particles present 

 in our surroundings, his sceptical critics sought to 



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