52 



MICRO-ORGANISMS AND FERMENTATION. 



accordingly divided into macrococci and micrococci (Fig. 10 a). 

 When the spheres occur in pairs, they are called diplococci (6); 

 they also appear in groups consisting of four individuals, 

 sarcina (6); or of a greater number, arranged irregularly, 

 or in chains, streptococci (c). From the coccus forms there is a 

 gradual transition to the rod forms bacterium, bacillus (e\ 



./ t' " A 



FIG. 10. 



Growth-forms of Bacteria : a. Cocci ; b, Diplococci and Sarcina ; c, Strepto- 

 cocci ; d, Zooglcea ; e, Bacteria and Bacilli ; /, Clostridium ; g, Pseudo- 

 filament, Leptothrix, Cladothrix ; h, Vibrio, Spirillum, Spirochsete, and 

 Spirulina ; i, Involution-forms ; k, Bacilli and Spirilla with cilia or 

 llagella ; I, Spore-forming bacteria ; m, Germination of the Spore. 



which vary greatly both in length and thickness. When the 

 rods are enlarged in the middle and taper towards the ends, 

 i.e., spindle-shaped, we have the clostridium form (/). If 

 the rods are elongated so as to become more or less thread- 

 like, they are called leptothrix (g), which may also occur as 

 pseudo-filaments (g), when several rods are arranged length- 

 wise, or as cladothriX) when they lie so close to one another 

 and in such a way that they become seemingly ramified ; a 



