PLATE 39 

 Bacterium marginale: 



A. — Part of a leaf from one of the original plants as received, showing the brown 

 veins in the infected and shriveled margins. X9 (about). 



B. — Part of a lettuce leaf, showing the shriveling and the marginal brown vena- 

 tion produced by spraying with Bad. marginale on March 2, 191 7. Photographed 

 March 7, 1917. X9 (about). 



