. Bulletin. Natural history; Natural history. August ,1945 Carter: Wetwood of Elms 421. Fig. 20.—The organism that causes wetwood of elm produces cells that are short rods with rounded ends and that occur singly or, rarely, in pairs or chains. XI,000. *• Fig. 21.—Cells of the wetwood organism have peritrichiate flagella. X 1,500. ing, whitish cream and viscid, and is accompanied by an odor of fermentation. A culture of the organism growing on cabbage infusion agar is shown in fig. 22. Growth in stabs in potato dextrose agar is abundant and is accompanied by the liberation of gas. This gas prod
. Bulletin. Natural history; Natural history. August ,1945 Carter: Wetwood of Elms 421. Fig. 20.—The organism that causes wetwood of elm produces cells that are short rods with rounded ends and that occur singly or, rarely, in pairs or chains. XI,000. *• Fig. 21.—Cells of the wetwood organism have peritrichiate flagella. X 1,500. ing, whitish cream and viscid, and is accompanied by an odor of fermentation. A culture of the organism growing on cabbage infusion agar is shown in fig. 22. Growth in stabs in potato dextrose agar is abundant and is accompanied by the liberation of gas. This gas produces fissures and frequently forces a portion of the agar up against the cotton plug or beyond the mouth of the test tube. At first the colonies are lens shaped to disk shaped. The medium remains unchanged in color. In shake cultures of potato dex- trose agar covered with a mixture of paraffin and vaseline, the organism develops abundant growth through the medium and produces sufficient gas within 20 hours to form fissures in the medium and to start raising the paraffin-vaseline seal. Growth on additional agars is as follows: abundant on cabbage infusion; moderate on lima bean and wood decoc- tion ;* scanty on bean pod, nutrient broth, *Wood decortion agar was made by adding 2 per cent agar to distilled water in which normal elm wood had been soaked for several days. corn meal, malt extract, prune, and plain agar plus 1 per cent, 5 per cent and 10 per cent dextrose; hardly visible on wort agar and on plain agar plus 20 per cent dextrose. No visible growth develops on 2 per cent plain agar. Streak cultures on potato plugs produce an abundant, fili- form, glistening, dark gray growth that darkens the potato tissue only slightly. The texture of the potato tissue is not visibly affected. Streaks on carrot plugs produce scant growth, consisting of one to a few beadlike glistening cream colonies. Carrot tissue is not visibly affected. No growth develops from streaks on apple pl
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