THE CUCURBIT WILT: TRANSMISSION 



143 



Fig. 75. — Longitudinal section of a cucumber stem, showing complete invasion 

 and destruction of the inner part of a bundle by Bacillus tracheiphilus. Photo- 

 micrograph by the writer in 1894. 





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Fig. 76. Fig. 77. 



Fig. 76. — Longitudinal section of a cucumber stem exposing two spiral v( 

 one occupied by Bacillus tracheiphilus; the other empty. For details of the bacteria 

 see a thinner section such as Fig. 77 or 78. 



Fig. 77. — Detail of Bacillus tracheiphilus from a cucumber vessel. Carbol 

 fuchsin stain. 



