CHAPTER 1 



THE NATURE, STRUCTURE, AND FUNCTIONS OF THE 

 BACTERIA : THEIR CLASSIFICATION, GENERAL BIOLOGY, 

 AND CHEMISTRY BACTERIA AND DISEASE 



THE Bacteria or Schizomycetes (" fission fungi ") are 

 minute unicellular vegetable organisms devoid of chloro- 

 phyll, which multiply by simple transverse division or 

 fission ; this distinguishes them from the yeasts in which 

 multiplication takes place by budding or gemmation. 

 A certain number of filamentous forms are also usually 

 included, but these are probably multicellular forms 

 belonging to the true fungi. The " fission plants " may 

 be placed in a sub-kingdom, the Schizophyta, which may 

 be divided into two classes : Class I, Schizophycese, the 

 blue-green algae, and Class II, Schizomycetes, the bacteria. 



The unicellular plants are sometimes termed the 

 " Protophyta." It must be understood that there are 

 connecting links between the different groups, and that 

 there is no sharp line of demarcation between them. 



The relation of the bacteria to other lower plants is 

 shown in the scheme on p. 9. 



The Bacteria have been supposed to have affinities with 

 the Fungi, with the Protozoa, or with the Cyanophycese. 

 There is little or no evidence to connect them with the 

 first two groups and not much with the last one, though 

 the resemblances here are greater. Though usually 

 regarded as simple forms, the Bacteria display considerable 

 morphological and structural differentiation and physio- 

 logical complexity and are by no means primitive forms. 



