ESSENTIALS OF BACTERIOLOGY. 



PART I. 

 GENERAL CONSIDERATIONS. 



CHAPTER I. 



BACTERIA. 



6ACTERIA (3cueT'7pioi>, little staff) is the name given to a group 

 of the lowest form of plants, very closely following the algse. 

 They were called Fission-Fungi or Schizomycetes (ff^f^w, to cleave, 

 jutf^, fungus), because it was thought that, as the Fungi, they 

 lived without the chlorophyll. The word fission was supplied 

 to distinguish them from moulds and yeasts, it denoting the 

 manner of reproduction. Since several bacteria have been 

 found to possess chlorophyll, and as a great many increase in 

 other ways than by simple fission the name of Schizomycetes 

 can no longer be applied, though the word Bacteria leaves much 

 to be desired. 



Classification. Ferdinand Cohn, in the middle of the present 

 century, was the first to demonstrate bacteria to be of vegetable 

 origin, they being placed previous to that among the infusoria. 

 He arranged them according to their form under four divisions. 



Cohn's System. I. Spherobacteria (globules). 

 II. Microbacteria (short rods). 



III. Desmobacteria (long rods). 



IV. Spirobacteria (spirals). 



As expressed at the present time, Micrococcus, Bacillus, and 

 Spirillum. This classification is very superficial, but because a 

 better one has not been found it is most in use to-day. 



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