. Bacteria in relation to plant diseases. Bacteria; Plant diseases. COBB S DISEASE OF SUGAR-CANE. 57 Witte's peptone 15, cane-sugar 15, agar flour , autoelaved for 15 minutes at 1 io° C. The surface growth was wet-shining and about a cubic centimeter of pale yellow slime accu- mulated in the V of each tube. The growth on potato-agarwas somewhat better than on beef-agar; there was a smooth, wet-shining, yellow streak (fig. 32), varying from scanty to abundant. On litmus-laetose-agar there is a very scanty to moderate growth, with slow but dis- tinct bluing and no reduction of the litmus. No
. Bacteria in relation to plant diseases. Bacteria; Plant diseases. COBB S DISEASE OF SUGAR-CANE. 57 Witte's peptone 15, cane-sugar 15, agar flour , autoelaved for 15 minutes at 1 io° C. The surface growth was wet-shining and about a cubic centimeter of pale yellow slime accu- mulated in the V of each tube. The growth on potato-agarwas somewhat better than on beef-agar; there was a smooth, wet-shining, yellow streak (fig. 32), varying from scanty to abundant. On litmus-laetose-agar there is a very scanty to moderate growth, with slow but dis- tinct bluing and no reduction of the litmus. No acid is formed. On Hunger's agar (Mr. Johnston's notes) there is a very noticeable difference in the growth, depending on whether the monobasic or dibasic phosphate is used. When the monobasic (acid) salt is used there is a growth rather light yellow in color, while with the dibasic salt it is rich yellow with paler edges, and is much more luxuriant, although not heaped up as in the case of Bacterium phascoli. Greig Smith gives the fol- lowing description of the organ- ism in glucose-gelatin plates: The colonies develop slowly. In 7 days at 220 C. they are 1 mm. in diameter, and appear as small, raised, viscid drops. When mag- nified 60-fold [see fig. 33] they appear round and uniformly gran- ular, like a thin yeast colony, the deep colonies like those upon the surface. In 20 days the colonies reach a diameter of 4 to 8 mm. and look like drops of yellow beeswax. The medium shows no signs of liquefaction, but when the colony is scraped or washed off a pit is revealed. Growth in the absence of glucose is similar but much slower (RGS.). In cane-juice gelatin-stabs there is a smooth, piled-up, restricted yellow surface growth. There is no liquefaction (possibly in some instances there was an unobserved slight liquefaction, ;'. c, a sinking in of the nail-head), no production of gas, no stain, and no formation of crystals. Greig Smith reports slow growth on gelatin in the presence
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