CHAPTER XI 



BACTERIA 



THERE is probably no scientific work more 

 wedded to the microscope than the study 

 of bacteria. We may learn a great deal 

 about birds or insects or rocks or minerals, without 

 any instrument but we can learn little of the bacteria 

 unless they are highly magnified. 



There is such an extraordinary amount of miscon- 

 ception concerning bacteria that, it will be time 

 well spent if we attempt to clear up all misunder- 

 standing at the start. Bacteria, often called 

 microbes or germs, are looked upon with consider- 

 able awe by most people, who associate them in 

 some vague way with disease. There is no denying 

 that many bacteria are responsible for certain 

 diseases; many more are perfectly harmless and 

 a goodly number are exceedingly useful. 



To enumerate all the bacterial activities would 

 require a large book but briefly, apart from the 

 disease-causing bacteria, they enter into the manu- 

 facture of cheese and butter, of wine and vinegar; 



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