DESCRIPTION OF PLATES. 



Plate I. Frontispiece. Calla bed in which all the callas, 1,000 in number, were 

 destroyed by the soft rot four years ago. Since that time three successful crops 

 of the i)lant have been grown in this bed under the writer's direction, this being 

 the third crop. 



Plate II. Fig. 1. — The organism that produces the soft rot of the calla, showing the 

 form of the individual, the development in chains, and the presence of flagella 

 (X 1,000). Fig. 2. — Development of colonies of the soft-rot organism on agar 

 plates at 18° to 25° C. The organism with which these plates were inoculated had 

 been kept dormant for two hundred and seventy-five days by withholding oxygen. 

 Nearly all the colonies are round. Only a few show a slight tendency to radiate. 

 Photographed three <lays after the plates were poured. (Natural size. ) Figs. 

 3, 4, and 5. — These figures were made from agar jilates which were inoculated 

 with the same organism as figure 2, but after it had been for a longer time exposed 

 to the air and had been transferre<I several times to fresh sterile beef broth. 

 These plates were three days old and had been k('])t at a temperature of from 

 18° to 25° C. 



Plate III. Fig. 1. — Agar plate colony of the calla organism three days old at room 

 temperature of about 20° C. The organism had been grown in l)eef broth 

 previous to making the agar plate. (Natural size. ) Fig. 2. — Agar plate colonies 

 of the calla organism three days old. Grown at a temperature of 37° C. for three 

 days, then kept for two days at about 20° C. (Natural size.) Fig. 3. — Tubes 

 from which agar plates were poured photographed three days after pouring the 

 plates; temjierature, about 20° C. The agar was inoculated with a beef- broth 

 culture of the calla organism. (Natural size. ) 



Plate IV. Fig. 1, A. — Stab culture of the calla organism in neutral gelatin twenty- 

 four hours after inoculation at 18° to 20° C. Fig. 1, B.— Stab culture of the 

 calla organism in neutral gelatin three days old at 18° to 20° C. Fig. 1, C. — Stab 

 culture of the calla organism in + 15 (acid) gelatin twenty-four hours after inocu- 

 lation at 18° to 20° C. Fig. 2.— Raw eggplant in petri dish. Pieces 1 and 4 

 were inoculated with the calla organism, while pieces 2 and 3 were left for con- 

 trol. The photograph was made three days after inoculation. 



Plate V. Fig. 1. — Raw radish in petri dish. Nos. 2 and 3 were inoculated with 

 the calla organism, while Nos. 1 and 4 were left for control. Photographed 

 three days after inoculation. Fig. 2. —Side view of same plate nine days after 

 inoculation. No. 2 was inoculated and No. 1 was left for control. 



Plate VI. A.— A cucumber inoculated with the calla organism. Photographed 

 two days after inoculation, when the contents were soft throughout, except the 

 spot near the stem end where the cucumber was inoculated. B. — A cucumber 

 used for control; i. e., it was treated in the same manner as A, except that the 

 calla organism was not applied to the punctures. 



Plate VII. Fig. 1.— Raw parsnip root in petri dish. The discolored pieces at 

 right and left were inoculated, while the upper and lower pieces were left for 

 control. Photographed three days after inoculation. (Natural size. ) Fig. 2. — 

 Raw carrot root three days after iiiocnlatiou with the calla organism. Pieces 2 

 and 3 were uioculated, while pieces 1 and 4 were left for control. (Natural size.) 



4b 



