VI LIST OP ILLUSTRATIONS. 



TEXT FIGURES. 



Fio. PACK. 



1 . Oozing of Bact. vascularum from Cut Surface of Australian Sugar-cane 5 



2. Cobb's Figures of Bact. vascularum 6 



3. Cane-plants Dwarfed by Bact. vascularum 9 



4. Bacterial Cavity under Terminal Bud in Sugar-cane Attacked by Bad. vascularum 15 



5. Radial Longitudinal Section through Leaf-sheath of Sugar-cane No. 4, Attacked by Bact. vascularum . 15 



6. Detail from fig. 5, showing how the Bacteria reach the Surface through Stomata 16 



7. Cross-section of fig. 5, including two vascular bundles 17 



8. Inoculated Cane No. 9, showing Sidewise Pushing of the Terminal Bud 17 



9. Cane Stripped of Leaves to show Dwarfing and Twisting of Terminal Bud (zigzag growth) due to 



Bact. vascularum 18 



10. Pushing of Buds in Inoculated Purple Cane No. 38 18 



: i . Longitudinal Section Showing Pushing of Buds and Red Nodal Stain in Stem of Sugar-cane Attacked 



by Bact. vascularum 19 



12, 13. Microscopic Appearance of Reddened Vascular Bundles of Sugar-cane Attacked by Bact. vascularum . 19, 20 



14. Pure Culture of Bact. vascularum Plated in 1902 from Australian Cane 20 



15. Nanism of Inoculated Sugar-cane 22 



1 6. Leaf of Sugar-cane showing White Stripes due to Bact. vascularum 23 



17. A Pure Poured Plate Culture of Bacterium vascularum from inoculated Cane No. 9 25 



1 8. Contents of Red Slime from Interior of Sugar-cane 9 months after Inoculating with Bact. vascularum 45 

 19, 20. Cross-sections of Vascular Bundles of Sugar-cane, showing Parts Occupied by Cobb's Organism. 49,50 



21. Early Stage in Occupation of a Bundle, Cane-plant No. 6 51 



22, 23. Longitudinal Sections through Inoculated Cane No. 6, showing Destruction of the Vascular Bundles. 52, 53 



24. Longitudinal Section through Inoculated and slightly Diseased Purple Cane No. 30, showing Red 



Bundles as Dark Lines 54 



25. Cross-section of Vascular Bundle of Sugar-cane Occupied by Bact. vascularum (the dark portions 



surrounding the yellow slime were a deep red color) 55 



26, 27. Bacteria (highly magnified) from Different Parts of Inoculated Cane-plant No. 6 55 



28, 29. Flagellate Rods of Bact. vascularum 55,56 



30. Rods of Bact. vascularum from a Young Culture on Nutrient Agar 56 



31. A Pure Culture, Agar Poured Plate, of Bact. vascularum from Plant No. 1 1 57 



32. Streak Cultures of Bact. vascularum on Potato Agar 58 



33. Magnified Colony of Bact. vascularum on Glucose Gelatin 59 



34. Growth of Bact. vascularum on Cane-juice-gelatin with and without Peptone 59 



35. Tear-drop Formation of Bact. vascularum on Slant Gelatin with Cane-juice 60 



36. Streak Cultures of Bact. vascularum on Potato 60 



37. Bacterium vascularum in a Petri-dish Agar Poured-plate (one-half exposed to sunlight) 66 



38. Crystals from an Agar Streak Culture of Bact. vascularum 67 



39, 40, 41. Cross-sections of Maize Stems, showing Bact. stewarli Oozing from Vascular Bundles. Figs. 39, 40, 



from plants shown in pi. 6 (natural infections), fig. 41, from artificially infected plants.. . 91,92,95 



42. Radial longitudinal Section through Basal Part of Stem of Diseased Sweet Corn from Long Island. . 98 



43, 44. Yellow Bacteria from Smear Preparations Made from Stems of Long Island Sweet Corn 98 



45, 46. Periphery of Portion of Corn-cob in Cross-section, showing Bacteria under and in Kernels .... 1 14, 1 15 



47. Section through a very immature Corn Kernel and its Supporting Tissues (the area occupied by 



Bad. stewarli in the base of the Kernel is drawn in solid black) 116 



48. A Detail from fig. 47, showing Bacterial Cavities and the Occlusion of Vessels 119 



49. Cross-section of the Infected Corn-husk shown in Vol. II, fig. 14, Inoculations of 1902 119 



50. A Detail from fig. 49, in the Vicinity of x, i. e., from another section in the series, showing stomatal 



Ooze of Bacteria 119 



5 1 . Surface View of an Infected Corn-husk showing Bact. stewarti oozing from a Stoma. (For appear- 



ance in section of a similar stoma, see fig. 50) 120 



52. Longitudinal Tangential Section through a Diseased Corn-husk, showing Substomatic Chambers 



filled by Bact. stewarti 1 20 



53. Bacterially Spotted Husks, same as Vol. II, fig. 14, but from a Naturally Infected Plant, i. e., one 



grown in the hot-house in 1908 from diseased seed 121 



54. Occlusion of Single Spiral Vessel by Bact. stewarti on the Periphery of a Cob (longitudinal view) . . 129 



55. Cross-section of Stem of Sweet Corn from Long Island, showing one Bundle with Occlusion of a 



Single Vessel by Bad. stewarti 129 



56. Section similar to fig. 55, but from Sweet Corn Inoculated by the Writer in Washington, in 1902, 



and showing entire Xylem Portion of the Bundle Occupied by the Bacteria (phloem free). ..... 130 



57. Section through lower part of a Diseased Sweet Corn Kernel, showing Relation of Parts, etc 130 



