8 



BACTERIOLOGY 



teria, Fig. 4, a; rods, in which the length exceeds the diameter, 

 Fig. 4, b-d; filaments, greatly elongated rods, Fig. 4, c ; commas 

 or curved rods, Fig. 4,/; spirals or serpentine forms, Fig. 4,g, //, /. 

 Rods may be still further divided into ovals, in which the 

 length scarcely exceeds the diameter, Fig. 4, b ; short rods, in 

 which the length is 2-4 times the diameter, Fig. 4, c ; and long 

 rods, in which the length is 4-8 times the diameter, Fig. 4, d. 



a b c c 



) 



s\*j 



\ 





t 



FIG. 4. Showing forms and grouping of bacteria. 



a cocci, b ovals, c short rods, d long rods, e filaments, /commas, g short spiral, ht long 

 spiral, Clostridium forms, k cuneate forms, s clavate forms, m capitate forms, n strep- 

 tobacilli, o streptococci, s diplococci, q staphylococci, r tetrads,/ streptospirilli, w sarcina. 



Spirals may also be divided in short spirals, the wave spiral, 

 Fig. 4, g ; and long spirals, which are multiples of the former, 

 Fig. 4, // and /. 



Special forms may also be noted which commonly appear 

 during sporulation and as involution forms. These are : Clos- 

 tridium forms, or rods swollen in the centre and attenuated at 

 both ends, Fig. 4, i ; cuneate forms, wedge-shaped, enlarged 

 at one end ahd gradually tapering toward the other, Fig. 4, k ; 

 clavate forms, as in Fig. 4, s ; and capitate forms, as in Fig. 4, k. 



