vni BINARY FISSION 8? 



long axis, like Hgematococcus (p. 25), and this double move- 

 ment produces the appearance of undulation. 



Most Bacteria are colourless, but three species {Bacterium 

 viride, B. chlorinufti, and Bacillus virens) contain chlorophyll, 

 and several others form pigments of varying tints and often 

 of great intensity. For instance, there are red, yellow, 

 brown, blue, and violet species of Micrococcus which grow 



Fig. 16. — Bacillus sttbtilis, showing various stages between single 

 forms and long filaments {Leplothrix). 



on slices of boiled potato, hard-boiled egg, &c., forming 

 brilliantly coloured patches; and the yellow colour often 

 assumed by milk after it has been allowed to stand for a 

 considerable time is due to the presence of Bacterium 

 xanthinum. 



All Bacteria multiply by simple^ transverse fission, the 



* process taking place sometimes during the motile, sometimes 



during the resting condition. Frequently the daughter-cells 



do not separate cftmpletely from one another but remain 



