2O4 The Story of the Bacteria 



cleaners but some of them have neither, and 

 while in the majority we admire the chaste 

 gilding and sumptuous upholstery of the 

 interior, and complacently reflect that at 

 length the law has forced builders of places 

 of amusement to afford a measurable degree 

 of security against being burned alive, those 

 elements of danger in large assemblies, more 

 important and more subtle than all the rest 

 put together, namely, inadequate ventilation 

 and cleaning, are seldom commented upon or 

 thought about. 



Recent studies have shown us that the 

 earlier and still prevalent conceptions of the 

 requirements of good ventilation were inexact. 

 It is commonly thought that in un ventilated 

 assembly rooms where many persons are 

 foregathered, the dullness, headache, and 

 "dopey" feeling, which everybody has ex- 

 perienced, are due to lack of oxygen and to 

 the accumulation in the air of carbonic acid 

 gas and various human poisons which the 

 people set free. 



But in fact these all appear to be of second- 

 ary importance. It has been shown by most 



