MICROBES, FERMENTS, AND MOULDS, 



INTRODUCTION. 



MICROBES AND PROTISTA. 



MICROBES are the most minute living things which 

 the microscope permits us to see distinctly, so as to 

 study their organization. They are for the most part 

 invisible to the naked eye, and even by the aid of a 

 simple lens. In order to form an exact idea of their 

 forms and structure, we require the strongest magni- 

 fiers of modern instruments, which enlarge the object 

 500, 1000, and even 1500 diameters. 



The word microbe has been recently introduced 

 into the French language ; it did not exist eight years 

 ago, and for this reason it will be sought for in vain 

 in most dictionaries. It was under the following cir- 

 cumstances that this term, now in such general use, 

 was invented by Sedillot, an eminent surgeon, whose 

 recent death is deplored by France. 



Those naturalists who have studied the most 

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