92 



THE CYTOLOGY AND LIFE-HISTORY OF BACTERIA 



Vegetative reproduction, in bacteria of this morphology, may take place 

 in one of two different ways, which correspond to the simple and complex 

 types of fission in eubacteria, although the resemblance is not exact. 



(6)— (§ 



a 



D 



(Reproduced from the Journal of General Microbiology.) 



Fig. 38 



ALTERNATIVE MODES OF DIVISION IN MYCOBACTERIA AND 

 CORYNEBACTERIA 



■fop — Proliferation of cells, followed by simple fission. 



Below — Fragmentation into individual cells, which by growth and division return to the 

 original condition. 



In actively growing cultures, rapid cell division takes place at the centres 

 of the bacilli, where the cells become very numerous, without much growth 

 o'i the bacterium, so that some cells may be reduced to narrow discs, although 

 the terminal cells retain their spherical or oval shape. This multiple cell 

 division is followed by fission of the bacterium. The new, terminal cells, 



Fig. 39 

 THE CYTOLOGY OF CORYNEBACTERIA AND MYCOBACTERIA 



(1) C. diphiherics stained by Neisser's stain, after heat fixation. The " typical morphology " 

 and " metachromatic granules " are seen. 



(2), (3), (4) C. diphthevice stained cytologically for cell walls (by tannic-acid-violet (2)) 

 and for the nuclear structures (by acid-Giemsa, (3), (4)). The bacilli are multicellular, and 

 reproduce in two characteristic ways ; by cell proliferation and simple fission, or by frag- 

 mentation. 



(5), (6) Similar preparations of a vaginal corynebacterium. 



(7), (8), (9) Similar preparations of M. fiibercidosis. Its structure resembles that of the 

 corynebacteria. 



(10) Cell wall stain of M. plilei. 



All at ■ 3000. 



