456 Journal of Agricultural Research voi. iv. No. s 



daily by sunken, reddish* brown streaks or patches (PI. LXV, fig. 2). 

 Generally in the case of prick inoculations on nasturtiums of the tall 

 variety adventive roots are formed at various points on the stem. These 

 remain rudimentary except where the stems are near the ground, when 

 they may become functioning roots. Check pricks failed to produce any 

 root formation. No adventive roots occurred on any of the inoculated 

 plants of the dwarf variety. 



MORPHOLOGY OF THE NASXtjRTIUM ORGANISM 



The organism is a short rod with rounded ends, 0.6 by 0.8 to i-'nx, 

 motile by means of one to three polar flagella. No spores or capsules 

 occur on any media. Chains of 10 to 15 individuals are formed in 0.5 

 and I per cent salt bouillon. Similar chains are formed in 0.5 per cent 

 salt bouillon by the Creedmore tobacco organism. 



STAINING REACTIONS 



With carbol fuchsin polar staining is obtained. The organism does 

 not stain by Gram's method and is not acid-fast. Flagella were demon- 

 strated by Lowitt's flagella stain. 



CULTURAL CHARACTERS 



In all the cultural tests made with this organism it agrees substan- 

 tially with Bacterium solanacearum Krw. Sm. Growth was studied in 

 the following media: Agar plates, slants, and stabs; gelatin plates and 

 stabs; potato cylinders; beef bouillon; fermentation tubes containing 

 water -f i per cent Witte's peptone -f i per cent dextrose, saccharose, 

 lactose, maltose, mannit, or glycerin; milk; litmus milk; Cohn's solu- 

 tion; Uschinsky's solution; and Fermi's solution. 



Growth is retarded by 0.5 per cent of sodium chlorid in beef bouillon, 

 is prevented by 2 per cent, and is very weak in i per cent. This is true 

 also for the Creedmore tobacco organism, which was used for comparison. 

 No record has been previously given for B. solanacearum in this medium. 



TEMPERATURE RELATIONS 



The optimum for growth is about 30° C. No growth occurs at 39° C, 

 very weak growth at 12° C, and none at 10° C. The thermal death- 

 point lies between 48° and 52° C. 



DESICCATION OF THE ORGANISM 



"When dried on sterile covers from young peptone-beef-bouillon cul- 

 tures and kept in the dark at room temperature (21° C), most covers 

 gave growth after 24 hours when dropped into suitable bouillon, very 

 few after 2 days', and none after 3 days' drying. The bacteria from 

 24-hour bouillon cultures were more sensitive to drying than those from 

 8-day-old cultures. 



