IO4 BACTERIA IN RELATION TO PLANT DISEASES. 



Above this cut 3 nodes are brown and the others farther up are yellow and show the bacterial ooze 

 distinctly on section. The middle internodes are white, with numerous yellow bundles. 



The plants LI I to I/XX were brought in and examined on October 27. All the plants 

 had good roots. The ears were in the edible "green-corn" stage. The tops had been 

 broken off in many cases. When not otherwise recorded, the parts, except leaves and male 

 inflorescence, were normal in appearance. Most of these plants were 3 to 4 feet high. 

 There had been a slight frost and a few of the leaves here and there may have been killed 

 as the result of the frost, but I think it unlikely, because in the same hill one plant would 

 have dry leaves and another not, and also because all of the remaining plants had more or 

 less green leaves. Many of these leaves were 3 to 3.5 inches wide. 



The leaves of these 19 plants were dried out and dead. The male inflorescence where 

 it was present was white and dry. The stems in all cases were green and normal in appear- 

 ance and many of the leaf-sheaths were alive, the blades being the dry part. 



LII. Cut 3 inches from base, nearly every bundle is occupied by the yellow bacteria. All the 

 middle internodes contain many yellow bundles. The organism is abundant in the bundles at the 

 base of each one of the five ears. It can be traced into the upper internodes of the main axis, but is 

 less abundant there. The basal 3 inches slit through shows much less browning in the nodes than in 

 any plant hitherto examined, but the basal node is brown. 



LIII. This is a very small plant. It has had a bad injury underground, and the height of the 

 plant is less than a foot. The injury referred to cut the stem at least half in two. No distinct indica- 

 tion of the disease in the upper part of the stem. The 2 basal nodes are brown, but the internode is 

 whitish. I can see no yellow or brown bundles in the internode. Probably the dwarfing was due to 

 the extensive stem injury. Not examined under the compound microscope. 



LIV. Stem cut 3 inches from the base, nearly every bundle shows an abundant yellow ooze. 

 There are 4 ears ; all show presence of bacteria at the base in the form of yellow ooze. Slit the base of 

 the stem longitudinally. There are 2 brown nodes with yellow stripes in the internodes. I also find 

 the organism moderately abundant 6 inches under the male inflorescence. Cut still higher up, that 

 is, immediately under the male inflorescence, the bacteria are still present. (Turned over the rest 

 of the plant to my colleague, Mr.Merton B. Waite.who stated that he found bacterial infection in the 

 bundles of every node and internode.) 



LV. Cut 3 inches from the base, the internode contains yellow and black bundles, but they are 

 much less numerous than in the preceding. Sliced longitudinally, the 3 lower nodes are brown ; the 

 internodes are white, with yellow and brown bundles. Cut i foot higher, there is almost complete 

 freedom from visible infection in the internode. This plant is much less infected high up than the pre- 

 ceding. The disease runs out entirely, so far as one can see with a hand-lens, at 1.5 feet under the 

 male inflorescence. One small ear and one large one; neither show any infection. 



LVI. This is a small plant, not more than 3 feet high. A cut 3 inches from base shows numer- 

 ous points of infection. There must be at least 50 bundles from which there is a yellow bacterial 

 ooze. The ear shows disease in a number of the inner husks in the shape of infection of the bundles, 

 water-soaked spots in the parenchyma and a yellow bacterial ooze on the inner surface of the husks. 

 The inner face of certain husks is the only place where the bacteria have been observed coming to the 

 surface. The base cut longitudinally shows 3 brown nodes and many yellow bundles. There are 3 

 brown nodes above this cut and 3 yellow ones higher up. The internodes higher up show numerous 

 yellow bundles. The yellow bundles run out into the base of the cob. 



LVII. Two ears, partially destroyed by insects and smut, show yellow bundles in the unde- 

 stroyed base. Cut 3 inches from the base, the main stem shows many bundles with the yellow bac- 

 teria oozing out in great quantities. The base slit longitudinally shows 3 brown nodes, the cut 

 bundles exuding yellow ooze. The internodes show very many yellow bundles. The disease appar- 

 ently runs out in the first node below the tassel. A small ear near the base of the stem also contains 

 bacteria in the bundles of the husks and in the base of the cob. 



LVIII. Cut 3 inches above the base, the stem shows bundles with a yellow ooze, rather few in 

 number. Plant cut i foot higher, in the internode, shows a yellow ooze from about 40 bundles. One 

 ear which was badly gnawed by larvae shows many yellow and brown bundles in the uninjured base, 

 and some of the inner husks show the yellow bacteria oozing out. The middle internodes of the main 

 axis, slit longitudinally, show yellow and brown bundles. When cut 8 inches under the male inflores- 

 cence, 2 or 3 bundles in the internode show a yellow ooze. Cut 0.5 inch under the male inflorescence, 

 the bacterial ooze is still plainly visible in one bundle. Above the basal cut there is i brown node and 



