254 BACTERIA IN RELATION TO PLANT DISEASES. 
INOCULATIONS OF May 13, 1895. 
Nineteen potato-vines were inoculated in the hothouse with B. tracheiphilus (cucumber- 
strain) the virulence of which was checked by inoculation into five cucumbers. The pota- 
toes were planted in 7-inch pots April 23. Large tubers were halved and all but two eyes 
cut out. At the time of inoculation each pot bore five or six shoots 8 to 10 inches high, 
growing rapidly and all very thrifty. The cucumbers (Cucumis sativus) were several months 
old, 2 to 3 feet high andin bloom. The bacteria used for inoculation were from a pure slant 
agar-culture (tube 1, May 11) made for this purpose from a glycerin-agar-culture (No. 8, 
May 1, reinoculated May 8). The growth was a characteristic, smooth, wet-shining, milk- 
white streak, much more sticky than the glycerine-agar-culture from which it was made. 
The weather was cool. The temperature in the hothouse at the time of inoculation was 
80° F. All the pricks made were deep. The needle and loop were flamed and cooled each 
time and thousands of living bacteria were thrust in. The potatoes received many pricks 
into young leaves and tender shoots. 
(171 to 189.) Potato (Solanum tuberosum). No result. 
(190.) Cucumber. The inoculation was made in a leaf borne on the tenth node (there were many 
nodes above). Many pricks were made near the midrib about half-way from the base of the blade 
to the tip. The blade was about 5 inches broad. Up to 1 p.m. May 27 (end of the fourteenth day) 
there was no trace of the disease, but at 5 p.m. of that day a very small area (less than one square 
centimeter) was wilted. The eighteenth day no constitutional signs had appeared—only wilt and 
shriveling of the pricked leaf-blade. Half of the latter was dry-shriveled and the rest hung flabby. 
There was no wilt above or below this leaf. Twenty-one days after the inoculation the pricked blade 
was wholly dry-shriveled and of a brownish color. The petiole was green and turgid except the 
upper inch which had become slightly yellowish and a little flabby. The leaves above and below were 
normal. Three days later there was still no wilt of the leaves above or below. The tip of the petiole 
of the pricked leaf was flabby. On the beginning of the twenty-fifth day the first secondary wilt 
appeared. This was in the first two leaves above the pricked one. The rest of the leaves were turgid. 
The general infection of the plant was very slow. June 8th (26 days after inoculation) the blade of 
the first leaf below the pricked one showed wilt (9 a.m.). At noon the blade of the third leaf up and 
of the second leaf down were wilted and that of the first leaf up had dry-shriveled the same as the 
pricked leaf. June 15 the vine had lost all its leaves by the wilt but the stem was yet green and turgid. 
A petiole was now cut across and the sticky bacterial ooze was pricked into the leaves and stems of 
pumpkin and squash. (No. 198 and others.) The same day the vine was cut and put into 75 per 
cent alcohol for microtome sections. It was not then examined microscopically but has been since— 
enormous numbers of bacteria being found in the vascular bundles of the stem. 
(191.) Cucumber. Many pricks were made in the middle of a leaf-blade (5 inches broad) to 
one side of the midrib. The pricked leaf was on the tenth node. The sixth day (2.30 p.m.) the leaf 
had wilted over an area of 1X3 cm. from the pricks outward, along both sides of a main vein nearly 
to the margin of the leaf. There was no wilt the preceding day at 4 p.m. The seventh day there was 
little change. Twenty-five hours later the bulk of the leaf was still turgid. The ninth day the whole 
leaf-blade drooped and the pricked side was drying out. Two days later the whole blade of the pricked 
leaf had shriveled. The petiole was still green and rigid. In the afternoon of the eleventh day the 
blade of the first leaf up began to droop decidedly on one side. The following morning it had partly 
recovered its turgor. At 2 p.m. the leaf-blade hung down flabby. The fourteenth day the blades 
of the first, second and third leaves up had collapsed and also those of the first and second down. 
The petiole of the pricked leaf was beginning to shrivel in the upper two inches. Four days later 
the leaf-blades were all down. The petiole of the pricked leaf had shriveled nearly to the base. 
The petioles below were turgid but those above were beginning to be flabby. 
(192.) Cucumber. Many pricks were made in the middle apical part of a leaf-blade about 4.5 
inches broad. The leaf was on the eleventh node. The sixth day (2° 30" p.m.) the leaf had wilted 
from the pricked part to the apex, a length of 4 cm. and a breadth of about 1 cm. The following 
morning there was little change. The eighth day the bulk of the leaf was still turgid. The day was 
cool, cloudy, and rainy. The following day about half of the blade of the pricked leaf had wilted. 
The petiole was rigid. The eleventh day the whole blade of the pricked leaf had shriveled. The 
petiole was still green and rigid. ‘I'wenty-four hours later the petiole of the leaf was still normal 
externally as was also the first leaf to either side of the pricked one. Four hours later the blade of the 
first leaf up had wilted. The fourteenth day the blades of the first and second leaves down collapsed. 
