23 



June 14. The leaves are dead; the bulb is sound externally. On sectioning, the 

 interior of the plateau was found to be diseased and there were also twenty -two 

 yellow bundles distributed through eleven different scales. These yellow bundles 

 were partially broken down and full of bacterial slime. That many of them were 

 tertiary infections (from the inoculated leaves by way of the plateau) was very 

 plain, since the yellow slime, while always distinct in the basal part of the bundle 

 next to the plateau, frequently became less abundant or disappeared altogether in 

 the middle or upper part of the scale. The greater part of the bulb was still 

 sound. No mycelium was present and there were no injuries from animals. 



SERIES 6 (ROMAN HYACINTHS). 



Four Roman hyacintlis (Hyacinthus aTbulus) were selected for this 

 series, wliicli A^as started Feljruaiy 7. The phints were line speci- 

 mens, in full bloom. Two of them were inoculated 

 in the middle part of tlie scapes (three scapes on each 

 plant) and the other two in the apical part of the leaves 

 (four leaves on one ]3lant and seven leaves on the other) . 

 The infectious material, alkaline beef-broth cultures 

 (Nos. 1 and 4, January 29), Avas put in l)y means of a 

 hypodermic syringe. Two plants in the same pot were 

 held as checks. 



j^esif?/. —The six inoculated scapes gradually shriv- 

 eled, but with no symptoms clearly attributable to the 

 action of the germs. Each of the eleven inoculated 

 leaves slowly developed narrow stripes corresponding 

 to the parts of the leaf suffused at the time of the 

 inoculation. These stripes did not appear until after 

 the seventh day. There was very little sidewise exten- 

 sion, and tlie downward movement was very slow. At 

 first tlie stripes presented a watef^soaked appearance. 

 Later they were pale yellow, with brownish veins, and 

 when dead and dry they were yellow-brown. No such 

 stripes appeared on any of the uninoculated leaves, of 

 which there were many. On June 15, Avhen all the 

 leaves were dead and gone, the bulbs were removed 

 from the i)ot and examined. Each had formed several 

 to many daughter bulbs, but neither in these nor in 

 the mother bulbs was there any trace of the yellow 

 disease. All were sound so far as could be determined by the 

 unaided eye. 



SERIES 7 (HYACINTHS). 



The seventh series of inoculations was made February 7, in the 

 same manner as the preceding. Vox tliis experiment I selected sixteen 

 vigorous plants of the single, white-flowered liaron van Tujdl, holding 

 fifteen plants of the sanu3 variety growing in the same box as checks. 

 The plants were in full bloom. Each bore five to seven good leaves, 

 three of which were inoculated in the apical part. Each plant received 



Fig. 2.— Inocu- 

 lated leaf of hy- 

 acinth No. 25. 



