30 BACTERIA IN RELATION TO PLANT DISEASES. 



organism is alive in cane after having been inoculated 8 months. Split longitudinally, bundles red 

 in some places, yellow in others, and black in still others. Material saved for plates. Cane perfectly 

 sound externally for many feet in the region of the diseased bundles ; the affected portion is in the 

 middle of the cane not at top or bottom. Longitudinally split, it shows bundles both yellow and 

 red. Up towards the top the cane is free from stain, healthy and sound. 



One large cane apparently inoculated, but labels are gone ; at least 10 feet long and 1.5 inches in 

 diameter ; not badly affected. Only a few red bundles at the nodes ; they do not run down into the 

 internodes at all. Largest cane we have cut. Has been no interference with growth. Red staining 

 in only 2 nodes probably those to which inoculated leaves ran, but these have fallen. Upper inter- 

 nodes perfectly sound and white. 



Another cane without labels but with leaf with label 306 lying near its base. Cane 10 feet high; 

 diameter 1 to 1.25 inches. Perfectly sound outside, and well grown. At height of 5 feet from 

 ground 3 red bundles, 1 of which shows a yellow ooze. Extreme base of cane sound inside and out. 

 Buds are well developed, but they are not pushing. Leafy portion cut away, leaving 5 or 6 feet; 

 sound at cut. Stem shortened 1 foot, beginning at top. Two bundles red. Another foot, there is 

 increase in number of red bundles, about ten, all in a group in the center of the cane. Yellow bac- 

 terial ooze from some. Shortened another foot, same diseased area continues. Bundles red and 

 brownish in perfectly sound tissue. Basal 3 feet of cane split longitudinally. Disease runs out about 

 20 inches from the base. Excellent evidence that the bacteria got in through the inoculated leaves. 



29 a and b. Cane 12 feet long, 1.5 inches in diameter; it has fallen down and rooted in places 

 and sent up some shoots, which are healthy. Top of cane sound. Base of cane, two red bundles 

 in sound tissue. Exterior of cane sound from base to top. At 4 inches above the base there are no 

 red or yellow bundles ; 9 inches above base cane sound ; 1 2 inches above base cane sound ; 2 feet above 

 base cane has one red bundle, which continues down the stem 8 inches and there disappears. At 1 

 foot higher, i. e., in the internode below one of the inoculated leaves, cane is sound. Location of 

 other inoculated leaf not known. Signs of disease are very slight, as there is discoloration in only one 

 internode. 



A cane about 10 feet high, 1 inch in diameter, no labels. Sound at top and base; probably an 

 inoculated cane, but can not tell. In middle part of cane there are three red bundles in sound tissue. 

 Outside of the cane sound. Trouble is confined to one node which looks sound outside. No stain in 

 flesh. 



Another cane 10 feet high, 1.25 inches in diameter. Top and base sound; 8 inches up sound; 1 

 foot up sound; 18 inches up sound; 2 feet up sound; entire cane sound. 



There were 5 large canes besides those above noted. All were sound at the top and base, and 

 none had labels. 



About an hour after cutting, four or five little yellow cirri pushed out from the ends of cut bundles 

 of cane No. 36. These ranged from 1 to 5 mm. long and were about 0.25 mm. in diameter. The red 

 stain present in the bundles was carried out on these cirri so that they were in some places red and in 

 others yellow. Looked at under the microscope, these cirri were simply masses of bacteria, enormous 

 numbers, in what seemed to be a pure growth. They were short rods, single, in pairs, fours, or eights. 

 Most of them were paired, i. e., rods with a plain constriction mid-way. None were motile. Stained 

 a cover and a slide. From the other end of this cane there were also drops of ooze which were masses 

 of bacteria. 



The cutting from No. 30 also shows drops of yellow and red ooze, which under the microscope 

 are seen to be made up of masses of bacteria. They are like those in 36, but more of them are in 

 small clumps (pseudozoogloea). 



The plates which were poured from plants 30 and 36 were made as follows : 



A tube of bouillon was inoculated abundantly by putting into it a good-sized piece of the inner 

 tissue containing vessels determined by the microscopic examination to be filled with the bacteria, 

 and letting it stand one hour. This tissue was then mashed with a sterile glass rod. As already 

 stated, these plants had not suffered materially from the disease, but some of the vessels showed im- 

 mense numbers of bacteria. The tissue was cut out with a cold, sterile knife. Neutral beef agar 

 poured at 41 to 38 C. was used; seven plates were poured direct and seven from the first dilution. 

 < )f those poured directly from tubes in which the tissue was mashed, one received six 3 mm. loops of 

 the bouillion and two others received each three 3 mm. loops, i. e., an enormous number of the bacteria. 

 Result: All dead. Not a colony developed on the agar plates. Canes, therefore, may have 

 this disease and recover from it. 



SERIES IV, 1903. 



The field experiment miscarried, owing, perhaps, to defective soil (a barren sand) on 

 which the canes from series 2 and 3 were set. 



