Fig. 10. Cross section of the petiole of a cauliflower plant inocu- 

 lated with a pure culture of 7?. olcracme. At a later stage than Fig. 

 9, .showing the almost complete collapse of the tissues, the enlarg- 

 ing and softening of the cell walls and the great increase in the num- 

 ber of bacteria. 



'-urn 







Fig. 12. B.oleranxu. Theflagella 

 stained by Van Ermegen's method. 

 The bacteria were taken from an 

 agar culture 18 hours old. 



Fig. 11. Cross section of a piece of turnip. This was taken from a 

 plant inoculated with a pure culture of B.nlerareae. Note the disorgani- 

 zation of the cells and the large numbers of bacteria in the intercell- 

 ular spaces. 



[32] 



