CELL FORMS 



51 



pointed, bulged, club-shaped or even slightly branched. 

 These peculiar and bizarre forms practically always occur 

 when some of the necessary conditions for normal growth, 



Fig. 36. — Spirilla. 



Fig. 37. — Vibrio forms of spirilla 

 Compare with Fig. 35. 



discussed in Chapters VI and VII, are not fulfilled. They 

 are best regarded as involution or degeneration forms for this 

 reason (Fig. 39). In a very few cases it is not possible to 

 obtain the organism without these forms (the diphtheria 



Fig. 38.— Spirochetes. 



Fig. 39. — Involution forms. The 

 organisms are tapering and branched 

 at one end. 



group). It is probable that these cell forms are normal in 

 such cases, or else conditions suitable for the normal growth 

 have not been' obtained. 



