34 BACTERIA IN RELATION TO PLANT DISEASES. 



on each one at a distance of 6 inches to a foot from the stem, that is, on the basal portion 

 of the blade of the leaf. None to be pricked into the stem. The rows extend east and west. 

 The rows selected are the first row on the north, third row from the north, fifth row from 

 the north, etc., until we reach the south end. This leaves as checks, beginning at the north, 

 the second, fourth, sixth, etc., rows. Each variety of cane is represented in the bed by two 

 rows, and there are eight varieties. This cane was planted in the autumn of 1904 and had 

 grown very slowly. This statement should be borne in mind, as it was evidently the govern- 

 ing factor in what followed. 



One-half the sugar-cane was inoculated May 22, using five potato cultures marked $ 

 made May 17 from an old indigo-blue litmus-milk-culture # of March 25, descended from 

 inoculated cane-plant No. 40. The other one-half was inoculated May 23 from six potato 

 cultures called X, made May 1 7 from an old indigo-blue litmus-milk-culture X, made March 

 25 and descended from cane plant No. 40 (pi. 1 1, fig. 12). All of these potato cultures were 

 covered with a bright yellow growth and were in good condition for use. Transfers from 

 them were made to as many more tubes of potato before beginning. The inoculations were 

 made as follows : 



The potato cultures were shaken until the yellow surface growth was washed off into 

 the fluid. Loops of this fluid were then spread on the surface of the leaf, and thirty or 

 forty delicate needle-pricks were made through this wet surface into the leaf. Generally 

 four 3 mm. loops of the cloudy fluid were placed on the surface of each leaf, one to the right 

 of the midrib, one to the left, and two along the groove of the midrib over an area of about 

 1.5 to 2 inches in length. Then the pricks were made through this fluid. Afterward about 

 three 3 mm. loops of the fluid were rubbed over the pricked surface on the under side of the 

 leaf, that previously mentioned being put on the upper surface. As soon as the leaf was 

 pricked it was covered from the bright light by pinning a piece of manila paper around it. 

 Two leaves were inoculated on each shoot. All were inoculated on the blade of the leaf 

 at a distance of 6 to 12 inches from the leaf-sheath. The varieties inoculated, and the num- 

 ber of shoots on each variety, beginning at the north end, are as follows: Cinta, 61 to 67 

 (7 shoots) ; Caledonia Queen, 68 to 77 (10 shoots) ; Louisiana No. 74, 78 to 82 (5 shoots) ; 

 Common Green, 83 to 87 (5 shoots); Blanca, 88 to 90 (3 shoots); Jamaica, 91 to 96 (6 

 shoots); Striped Green, 97 to 99 (3 shoots); Crystalina, 100 to 105 (6 shoots). Each leaf 

 has a wooden label bearing its inoculation number. 



On June 13, 1905, the condition of the cane leaves inoculated May 22 was as follows, 

 all of the uninoculated leaves being sound: 



Cinta. 



61 A. Begins to show white stripes in and above the pricked area. The stripes are visible 6 inches above the pricks. 



6 1 B. Stripes are visible 9 inches above the pricks. 



62 A. Begins to be white; bleached in pricked area and above it for a few inches. 



62 B. White stripes in the pricked area and extending downward some inches. 



63 A. White stripes in the pricked area, and up and down for a short distance (2 to 3 inches). 



63 B. Shows white striping in pricked area. 



64 A. White striping in the pricked area, extending upward 2 or 3 inches. 



64 B. Same as 64 A. 



65 A. Same as 64 A. 



65 B. White striping, and a red stain in the midrib above and below the pricks. 



66 A. Faint striping in the pricked area and extending upward 4 inches, downward I or 2 inches. 



66 B. Faint white striping in the pricked area. 



67 A. Pricked area dead to either side of the midrib, and white around the dead area. 



67 B. White striping in the pricked area and red stain in the midrib for about an inch. 



Caledonia Queen. 



68 A. White stripes in the pricked area, extending upward 4 inches and downward about 3 inches. There are little 



brown dead specks in some of these white stripes, not only on this plant but on the preceding plants. 



68 B. Slight signs in the pricked area. 



69 A. Same as 68 B. 



69 B. Yellow and red striping in the pricked area. 



70 A. White striping in the pricked area. 

 70 B. Same as 70 A. 



