THE STORY OF THE BACTERIA. 



It is not unlikely that the dried diphtheria 

 germ may, from faulty plumbing or dry traps 

 in the pipes, be blown into rooms along with 

 the sewer gas, and that thus the disease is 

 sometimes communicated without direct con- 

 tact with an infected person. 



Pneumonia. 



Pneumonia, in its more common phases, is 

 another of the diseases which we believe to 

 be caused by bacteria. The germ which pro- 

 duces the trouble has been many times sepa- 

 rated and carefully studied. It is called the 

 Pneumococcus. 



So frequently does this disease follow ex- 

 posure to cold or wet, and so often does it 

 begin with symptoms which resemble those of 

 an ordinary cold, that it was long believed to 

 be, and still is popularly regarded, as usually 

 caused by these exposures. But most of those 

 who have carefully studied the disease by the 

 use of the modern scientific methods of re- 

 search are disposed to believe that the expos- 

 ure to cold and wet and other less well-defined 

 conditions which were formerly regarded as 



