246 BACTERIA IN RELATION TO PLANT DISEASES. 
The petiole was still turgid and none of the other leaves were affected. Twenty-four hours later the 
tip of the petiole of the pricked leaf had begun to shrivel. The blade of the first leaf down had 
shriveled but the first leaf above showed no sign of the wilt in spite of the fact that the first internode 
below was three times as long as the first one above. The tenth day the first leaf up had collapsed. 
(109b.) Muskmelon. A small vine in the same pot as the preceding was pricked on the blade 
of one leaf. 
The morning of the fifth day one-eighth of the inoculated leaf (the apical pricked portion) had 
become dull-green and wilted. Twenty-four hours later the whole of the blade of the pricked leaf 
had collapsed. ‘Two days later the pricked blade was dry shriveling. ‘The petiole was still turgid 
and none of the other leaves showed any trace of the wilt. The following day half of the petiole of the 
pricked leaf had shriveled and the blade of the first leaf up had collapsed. The next day (afternoon) 
the upper part of the stem had wilted. The vine was cut and put into alcohol for study of location 
of bacilli by means of paraffin sections. They were found abundant in the vessels of the stem on 
microscopic examination. 
(109c.) A small melon in the same pot as 109a@ and 109) was held as a check. It remained 
healthy. 
(110a.) Muskmelon. A small vine was pricked on the blade of one leaf. 
The fifth day seven-eighths of the pricked blade had wilted. Twenty-four hours later the whole 
of the leaf-blade had collapsed. T'wo days later the pricked blade was dry-shriveling, the petiole 
turgid. The blade of the first leaf down, which had begun to show signs of wilting the previous after- 
noon, had collapsed. The first leaf up was still normal. ‘Twenty-four hours later the petiole of the 
pricked blade was flabby half-way down. The blade of the first leaf down had shriveled and that 
of the first one up showed very slight signs of loss of turgor. The first internode above was not half 
as long as the first one below. The next day the upper part of the stem was wilted and the vine was 
cut, brought into the laboratory and put into alcohol for sections: ‘These when examined under the 
microscope showed the presence in the vessels of numerous bacteria. 
(110b.) Muskmelon. The blade of the first true leaf of a small vine was pricked and inoculated. 
The fifth day about one-fifteenth of the pricked leaf-blade had wilted in a small spot on one 
side near the apex and within the pricked area. Twenty-four hours later about three-fourths of the 
leaf-blade hung flabby. Two days later the pricked blade had begun to dry-shrivel. One cotyledon 
and the next leaf above the pricked one had begun to wilt. The following morning the petiole of the 
pricked leaf had begun to wilt at the apex. The blade of the first leaf up had wholly collapsed. 
January 13 the upper part of the stem was wilted and the vine was cut and put into alcohol. Sec- 
tions examined under the microscope showed the presence of bacteria in the bundles of the stem. 
(110c.) A vine growing in the same pot as 110a and 6 was held as a check and remained free 
from the wilt. 
(111a.) Muskmelon. The blade of one of the leaves of a small vine was pricked and inoculated. 
The fifth day over one-half of the pricked leaf blade (apical pricked part) had wilted. By the 
following morning the whole leaf had collapsed. ‘Two days later the first leaf above the pricked one 
had begun to wilt. (Since 3 p.m. the preceding day). ‘The morning of the ninth day the first leaf 
above had shriveled and the wilt had invaded the petiole of the pricked leaf. The plant was now 
removed and examined microscopically. ‘The vessels were found to contain bacilli a part of which 
were motile. 
(1116.) Muskmelon. A vine growing in the pot with 111@ was pricked on one of its leaf-blades. 
The eight day there was no trace of the wilt, but 24 hours later about one-fourth of the apex and 
one side of the pricked blade had wilted and changed to a dull green. ‘The wilt began in the pricked 
area. ‘The time from the insertion of the bacteria to the appearance of the wilt was about 8} days, 
i. e., wilt appeared on the ninth day. The tenth day the stem was still turgid. Vine 1116 was the 
last of the eight melons to show the disease. A microscopic examination was made and bacteria 
were demonstrated in the bundles of the stem. 
(111¢.) A vine growing in the pot with 111a and 6 was held as a check and remained free from 
the wilt. 
(112.) Japanese Pear (Pyrus sp.). A small green shoot, 2 inches long, and a half-grown leaf of a 
Japanese pear seedling were pricked carefully. 
The ninth day there was no trace of the disease, nor did any signs appear later on. 
(113.) Cucumber (Cucumis sativus). An old cucumber vine growing in one of the insect cages 
(No. 38) in which infection had failed was pricked in the apical portion of one leaf-blade. The after- 
noon of the seventh day theré were no signs of the wilt, but at 10 a.m. of the following day about one- 
sixth of the blade had wilted in the pricked area (fig. 66). The lowest sign of wilt was 1.5 cm. from 
the base of the blade, and the petiole was 5.5 cm. long. Thus there were 7 cm. of healthy looking 
tissue separating the diseased part from the stem. ‘The leaf was now cut away close to the stem to 
