BACTERIA 



245 



some species these daughter rods separate very readily, while in 

 others they hold together for some time, making a long and fine 

 thread which later separates into the separate rods. Beggiatoa 

 forms long filaments of short cells similar to those of Oscillatoria 

 but lacking the blue-green color. The screw or spiral forms are 

 found in the genera Spirillium, Vibrio, etc. They also multiply 

 by cross division of the cells. The round, or spherical, forms are 

 found in a number of different genera according to the method of 

 association of the individuals. In Micrococcus (minute berry) the 

 rounded cells divide into two which quickly separate. In Strepto- 

 coccus with rounded cells, the cells after dividing remain in chains 

 similar to the bead-like chains of Nostoc. In Sarcina the rounded 

 cells divide in two or three directions, the cells remaining held 

 together in small cubical groups for a time. 



393. The work of bacteria in decay, fermentation, and 

 disease. For a discussion of this see paragraphs 220-223, which 

 should be studied in connection with this chapter. 



394. Comparative review of the bacteria. The bacteria 

 resemble the fungi in that chlorophyll is absent. Because of 

 their method of multiplication by simple division, or cutting in two 

 of the cells, which is sometimes called fission, they are called 



.fission fungi or Schizomycetes, and by some are classed with the 

 fungi. But this method of fission is like that of the blue-green 

 algae, which they also resemble in the variety of forms and asso- 

 ciation of cells, as well as in the simple condition of the proto- 

 plast, and the slimy covering of the cell walls. For these reasons 

 some consider them more closely related to the blue-green 

 algae, and place them in a class called Schizophycecz, with two 

 sub-classes, the Cyanophyceae (blue-green algae) and the Schizo- 

 mycetes (Bacteria). Still others place them in a class (Schizomy- 

 cetes) distinct from either the fungi or blue-green algae. This 

 seems to be the better arrangement. 



