26 BACTERIA I FORMS AND REPRODUCTION 



done before it is known what are the differences and 

 relationship of these so-called species and how many are 

 really distinct. There is little doubt that many of them 

 are the same, and a reduction of names must take place 

 in the future. Classification and registration, accord- 

 ing to some scheme such as that suggested on p. 60, 

 would facilitate rapid and easy reference and comparison 

 of all bacteria, and students of bacteriological science 

 should adopt a plan of this kind in describing new 

 forms. 



6. In addition to the simple types of bacteria already 

 described there is a large family of organisms resembling 

 bacteria in the shape of their individual cells and mode 

 of reproduction, but the cells are enclosed in long, 

 thread-like, tubular sheaths which may be simple or 

 appear branched. Some of these, such as Cladothrix 

 dichotoma (p. 128) and species of Crenothrix, are not 

 uncommon in impure water and in soil. 



7. The following scheme of classification adopted by 

 Migula, although imperfect in some respects, is as satis- 

 factory as any : 



Order I. EUBACTERIA. Cells colourless, or occa- 

 sionally containing chlorophyll. 



Family I. COCCACE^E. Cells globular when free. 

 Division occurs in one, two, or three planes with 

 the formation of chains, plates, or cubical packets. 

 Spores rarely formed. 



Genus I. Streptococcus. Cell-division in one plane, 

 the cells usually remaining attached in 

 the form of a string of rjearls. (Fig. 9.) 

 , 2. Micrococcus. Cell-division in two planes. 



