276 BACTERIA IN RELATION TO PLANT DISEASES. 
A big loop of the fluid, containing many thousand bacteria (some of which were motile, 
as determined by examination under the microscope) was put on the clean surface of the 
leaf, spread a little and then rapidly pricked in, taking special care to make the needle- 
holes as small as possible. The afternoon was cloudy, rainy, and cooler than the 10 days 
preceding. On account of the cloudiness and moisture in the air the pricks were not covered 
over with papers. The plants were examined every day for the first 8 days and frequently 
after that. “Twenty-four plants were inoculated. 
(355.) This plant was 18 inches high and very thrifty. The inoculation was made on the sixth 
leaf 9 inches away from the stem. The pricked leaf-blade was 5 inches broad. Up to the morning of 
July 21 there was no trace of the disease but at 3 p.m. of the same day about 0.5 sq. cm. on one side 
of the pricks was wilted. The following morning there was only a very slight change. By noon of 
the seventh day the wilt covered about 10 sq. cm., and reached half-way down the blade. The leaf 
was now cut off close to the stem with a hot knife. Four days later the vine was normal, apparently, 
except for a droop of the first two blades below and a fainter one of the first two above the node which 
had borne the pricked leaf. I filled the pot several times with water but an hour later the absorption 
of the water had not relieved the droop of the foliage. The next day in the afternoon the first two 
leaves below were cut away. They had not recovered their turgor. Three days later the first leaf up 
was gone (removed by someone), but the blades of the next four up showed the wilt. The eighteenth 
day the blades of the second and fourth leaves up were shriveled but the petioles were turgid. The 
fourth leaf was on the same side of the stem as the second. The blade of the third leaf which was on 
the opposite side was flabby but had not yet shriveled. The blades of the fifth, sixth, seventh, and 
eighth leaves up were drooping. The others were turgid The twenty-third day after inoculation 
all the leaves were shriveled and the stem itself was beginning to shrivel. The vine was about 
5 feet long, i. e., it trebled in length after being inoculated. It was staked up. 
(356.) This was a thrifty plant about 28 inches high. The sixth leaf was pricked 10 inches from 
the stem. The pricked leaf-blade was 6 inches broad. The sixth day no signs had appeared but at 
noon of the following day there was a slight wilt in the pricked area and 2 days later this wilt covered 
about 5 sq.cm. The eleventh day (9 a.m., July 27) the pricked part had dried out and the wilt had 
increased only slightly (1 to 2 sq.cm.). At 3" 30" p.m., however, the wilt covered an area of about 
10 sq. cm. The leaf was now cut off near the stem with a hot knife. Twelve days later no further 
signs had appeared, but the seventeenth day after the removal of the pricked leaf (28 days after 
inoculation), the blade of the first leaf below and of the first and second up were flabby. Examined 
microscopically the petioles of these three leaves were found to contain bacteria. 
(357.) This plant was 19 inches high. The inoculation was made 8.75 inches from the stem. 
The pricked leaf-blade was 5 inches broad. ‘The fifth day, at 10 a.m.,there had been no change in 
the appearance of the pricked leaf, but at 1 p.m., there was a slight wilt. At 3 p.m. I removed the 
leaf at the base with a hot knife, about 2 sq. cm. in and around the pricked area, having wilted 
distinctly. None of the other leaves ever showed any trace of the wilt. On September 23 (69 days) 
the plant was still living and free from the disease. 
(358.) This vine was 20 inches high and thrifty. The sixth leaf-blade was 5 inches broad. It 
was inoculated 7.5 inches from the stem. ‘The sixth day the pricked leaf still presented a normal 
appearance, but the following day at noon there were about 3 sq.cm. of wilt in and around the pricked 
portion. Two days later (hot again) the wilted area had increased to 5 or 6 sq.cm. The tenth day 
there was a bad wilt of the pricked blade, mostly without change of color, but which I could not 
overcome by copious watering. The next morning the leaf-blade had changed color throughout (the 
characteristic dull green) and the outer three-fourths of the petiole was flabby. I did not remove this 
leaf. The twenty-third day the blade of the first leaf down and those of the first three leaves up had 
wilted. The petioles were turgid. 
(359.) ‘This plant was 17 inches high and thrifty. The fifth leaf-blade which was 6.5 inches 
broad, was inoculated 8 inches from the stem. The fifth day, at 10 a.m. no signs had appeared but 
at 1 p.m. there was slight wilt in and around the pricked area. At 3 p.m. I removed the leaf with a 
hot knife, cutting the petiole close to the stem. About 3 sq. cm. of the leaf had wilted in the pricked 
area, and immediately around it. The eighteenth day (13 days after the removal of the pricked leaf), 
the foliage drooped a little, but it was doubtful whether this was due to the disease. The day was 
hot, still and cloudy. I watered the pot which had become rather dry, but this did not cause the 
leaves to recover their turgidity. Five days later (August 8) the blades of three additional leaves 
were wilted. 
(360.) This plant was 19.5 inches high. The fifth leaf was inoculated 9.5 inches from the stem. 
The pricked leaf-blade was 5 inches broad. The eighth day there was no trace of the wilt but the 
