JONES' SOFT ROT OF CARROT, ETC.: CAUSE 



241 



them separate in this volume, but further comparisons are 

 necessary. 



Technic. It is not difficult to isolate this organism, since 

 very often it occurs almost unmixed in the decaying tissues. 

 If the advancing margin of the rot is selected and the surface 

 organisms are destroyed by pressing a hot spatula on the part 

 selected (which may be the sound surface near the rot), one may 

 then dig through the burned surface and into the rotted area with 

 little danger of external contamination and the certainty of ob- 



FIG. 183. A, Bacillus carotovorus L. R. J., and B, Bacillus apiovorus Wormald, 

 in gelatin stabs at the end of 5 days at 20C. 



taining on the poured plates almost or quite a pure culture of 

 the parasite. The organism is easily identified by its rapid 

 disintegrating action on raw carrots or turnips and by its 

 cultural peculiarities. As here described it can not be distin- 

 guished with certainty from Bacillus phytophthorus (Xo. VII) 

 by its behavior on raw potato, nor by its growth in thin-sown 

 gelatin plates, as I formerly supposed (compare Figs. 206 and 

 212A with a, b of Fig. 205). 



For inoculation experiments, roots of various kinds may 

 be selected and also fleshy above-ground parts. The work may 



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