JONES SOFT ROT OF CARROT. ETC. : CAUSE 



237 



The growth on steamed potato cylinders forms a slightly 

 raised, wet-shining, smooth, cream-white covering, with a slight 

 evolution of gas and the conversion of starch into amylodextrin. 



15 days 



B 



FIG. 179. Fermentation tubes with potato juice: A. Jones 3a (original 

 Bacillus carotovorus) from Wisconsin in 1919. Gas in 24 hours. The gas in 48 

 hours and in 15 days is also indicated. B. Jones 3a (long in my laboratory). 

 No gas in 4 days. Amount of gas in 15 days is indicated. Good growth in both 

 tubes. B rots calla lily, A does not. B also rots young carrot tops. 



Gas is also formed from steamed carrot cylinders and the gray- 

 white bacterial layer is seldom thick enough to hide the orange 



