THE CROWN gall: technic 445 



Fig. 340. — A. Crown-gall teratoma produced by needle pricks on cut inter- 

 node of Nicotiana tabacum using hop strain of Bacterium tumefaciens passed through 

 sunflower in 1915. Photograph shows fused tumefied leaves, and sprouts growing 

 out of all parts of them. At A', X, X, shoots 3 and 4 inches long were cut away. 

 Inoculated March 1, 1918, with 14-day agar-streak culture. Photographed May 

 8, 1918. Natural size. 



B. Same phenomena as in A, but on a petiole of Nicotiana sylvestris. Hop, 

 colony 1, check on flask N. Inoculated January 16, 1917. Photographed March 

 2, 1917. X 2. There is a continuous tumor on the margin of the petiole with 

 leafy sprouts in five places (A' — X). 



