BACTERIA AS PLANTS. 



are prepared to believe them capable of producing 

 changes wherever they get a foothold and begin 

 to grow. Their power of feeding upon com- 

 plex organic food 

 and producing chemi- 

 cal changes therein, 

 together with their 

 marvellous power of 

 assimilating this ma- 

 terial as food, make 

 them agents in Na- 



ture of extreme 

 portance. 



FIG. 9. Showing various shaped 

 rods. 



DIFFERENCES BETWEEN DIFFERENT SPECIES OF 

 BACTERIA. 



While bacteria are thus very simple in form, 

 there are a few 

 other slight varia- 

 tions in detail 

 which assist in dis- 

 a tinguishing them. 

 The rods are some- 

 times very blunt at 

 the ends, almost 

 as if cut square 

 across, while in 

 other species they 

 are more rounded 

 and occasionally 

 slightly tapering 

 (Fig. 9). Some- 

 times they are sur- 



d, Bacteria showing the supposed roun d e d t)V a thin 

 structure in which x is the nucleus, , 



and v the protoplasm. layer of some gelat- 



FIG. 10. Bacteria surrounded by cap- 

 sules : a and b represent zoogloea ; 

 c, Chains of cocci with a capsule ; 



