486 



BACTERIAL DISEASES OF PLANTS 



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FIG. 364. Ricinus stem in longitudinal section showing tumors produced 

 by exposure to the vapors from 0.2 cc. of a 20 per cent solution of monobasic 

 ammonium phosphate held in a small serum tube resting on the next septum below. 

 The unopened internode above shows its base also tumefied. 



