SYMPTOMS^ WHICH RKSULTKD. 13 



SYMPTOMS WHICH RESULTED. 



The history of this phint. which wtis t'xaniiiuHl noarly every day, 

 is as follows: 



December 19, 189ii. — Plant inoculated. 



December 28. — A slight yellowing of part of the pricked areas. 



December 30. — Yellowing and wilt over the whole of the pricked area on one leaf 

 and over one-fourth of the pricked area on the other leaf. 



Jainuir!/ J, 1897.— A marked progress of the disease on each leaf. The wilt now 

 involves from 5 to 8 square centimeters on each leaf, and has run out to the margin 

 of each leaf near the apex. 



Jaiimin/ 4. — The wilt now involves from 10 to lo .^^ijuare centimeters on each leaf. 



Jamumj 5.— The wilt is still confined to the two inoculated leaves, about 30 square 

 centimeters on each leaf blade being involved. The advancing part of the diseased 

 area is dull green and flabby. The brown veining on these leaves is not nearly so 

 conspicuous as in the cabbage and kale plants which were inoculated at the same 

 time and from the same cultures. 



January IG {£8th'day).—\Jp to this time there have been no constitutional symp- 

 toms — that is, no leaves have shown symptoms except those which were inoculated. 



Februari/ 9 {52d day) .—T\\\s plant is now badly dwarfed and the top is dying. 

 The four large outer leaves which remain have shriveled nearly to their base, and 

 the bundles in the base of the petioles are plainly blackened. One small leaf is now 

 wilting and shows a distinct blackening of its veins. One other small upper leaf is 

 still green and normal in appearance. This leaf is but slightly developed. 



The plant was now pulled up and e.xaniined. The rootlets were 

 sound. The main root axis, which was about 3 inches long and one- 

 half inch in diameter in the largest part, was smooth, white, and .sound 

 externally. The root was now washed and inspected critically. A 

 most careful examination of the surface of the root gave no indication 

 as to the cause of the disease. The root was then cut open cross- 

 wise in three places, namely, at the top. in the middle swollen part, 

 and at the base of the swollen part. Tn the upper cut, which was 

 made about one-eighth inch under the crown of leaves, the bundles 

 were decidedly black, and many were occupied by the bacteria; there 

 were various small bacterial cavities but no large cavity. In both of 

 the other sections of the root there were small cavities here and there, 

 the affected xylem was pale brown, and in the middle part the whole 

 inner tissue seemed to be softening. The bark part of the root was 

 perfectly sound, 



TECHNiaUE EMPLOYED IN STUDY OF DISEASED PLANT. 



When examined microscopically, the vessels of some of the bundles 

 were found to be full of bacteria. The vessels of other bundles were 

 free, or tilled in part. No fungus threads were present. The root 

 had a turnipy smell when cut. Before putting the specimen into 

 alcohol two tubes of potato were inoculated from the interior. Both 



