228 



BACTERIAL DISEASES OF PLANTS 



FIG. 168. FIG. 169. 



FIG. 168. Surface and side view of a raw potato tuber (Green Mountain) 

 streaked 4 days, at 23C., with Bacillus carotovorus from a gelatin colony (3o, 

 long in my laboratory). The right-hand figure shows the depth to which the rot 

 has penetrated. Photographed Jan. 16, 1916. 



FIG. 169. Potato plant, variety Green Mountain, one shoot of which has 

 been inoculated 7 days with Bacillus carotovorus. Inoculated shoot dwarfed 

 and wilting with internal brown streaks. Organism less active than Bacillus 

 phytophthorus. Photographed Feb, 8, 1915. 



from same (4-day) bouillon culture of Bacillus carotovorus. No. 1 was flabby, No. 2 

 was turgid. Left check omitted. Time, 3 days. 



B. Same as A, but at the end of 6 days at room temperature (25C.) in a large 

 culture-dish. The inoculated half of the flabby carrot now shows a slight rot 

 at the top where an unusually large amount of the cloudy bacterial fluid was 

 deposited, i.e., much more than on the badly rotted piece. Experiment of May, 

 1915. Four days later there was little change. Right check omitted. This was 

 still sound. 



