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PLANT BACTERIA, VOL. 2. PLATE 20 
< YELLOW DISEASE OF HYACINTHS. 
(1) Cross-section of bulb, showing every scale infected except two in center. Haarlem, 1906. (2) Check-tube of litmus milk. 
G) Bacterium hyacinthi 10 days in litmus milk at 15° to 20°C. (4) Bacterium hyacinthi 22 days in litmus milk at 23° C. 
(5). Plant 79, variety blue Baron van Tuyll, inoculated through the flowers. Painted after 17 days. (6) Cross-section of infected 
bulb-scale. The ok of the parenchyma contain starch grains, but only a few are indicated. The xylem and adjacent parenchyma 
are disorganized ; the phloem is uninjured. After Wakker. (7) Cross-section of a bulb, showing secondary infection, The center 
is invaded by a soft white rot and by mites. Haarlem, August, 1906. (8) Outer face of a badly diseased scale. (9) Inner face of 
badly diseased bulb-scale. (10) Inner face of badly diseased bulb-scale. (11) Vertical section of a bulb, showing a secondary 
infection ; the base is occupied by fruiting hyphae of a Penicillium. All from Haarlem, 1906. 
