12 ILLUSTRATIONS. 



Page. 

 Plate XX. Fig. 1. — Nematode galls on Stizolobium. Fig. 2. — Natural crown- 

 gall of rose 201 



XXI. Hop on sugar beet 201 



XXII. A. — Daisy on salsify. B, C. — Poplar on sugar beet 201 



XXIII. Crown-gall on white poplar from Newport, R. 1 201 



XXIV. A. — Arbutus on sugar beet. B. — Grape on sugar beet. C. — Pop- 



lar on grape 201 



XXV. Cultural characters: Colonies and streak on agar, growth in milk. . 201 

 XXVI. A. — Photomicrograph of incipient tumor on rib of daisy leaf. 

 B. — Photomicrograph of cross section of very young tumor on 



daisy stem 201 



XXVII. Photomicrograph of vertical section through a small gall on a 



tobacco stem 201 



XXVIII. Photomicrograph of cross section of a daisy stem, showing a very 



early stage of the tumor 201 



XXIX. Photomicrograph of section of a young tumor on tobacco with tran- 

 sition to normal tissue 201 



XXX. Photomicrograph showing section of an incipient metastatic tumor 



in a daisy petiole 201 



XXXI. A. — Bacterial apple blight entering SpitzeAberg apple through a 



hard gall. B. — Destructive gall on blackberry from Wisconsin. 201 

 XXXII. Photomicrograph showing nests of rapidly proliferating cells in a 



daisy gall 201 



XXXIII. A,B, C. — Inoculated crown-gall and hairy-root on crucifers. D. — 



Hairy-root of apple inoculated on quince 201 



XXXIV. Tuberculosis of sugar beet 201 



XXXV. 1. — Willow gall on willow. Result of a pure-culture inoculation. 



2. — Quince knot from North Africa 201 



XXXVI. 1. — Beet on beet; slow-growing tumors due to pure-culture inocula- 

 tions. 2. — Root galls on hothouse lettuce 201 



TEXT FIGURES. 



Fig. 1. Flagella of Bacterium tumefaciens from daisy 107 



2. Involution forms of daisy organism after 2 weeks in bouillon at 0° C. . 107 



3. Daisy organism; slime from pellicle on beef-bouillon culture 3 weeks 



old 108 



213 



