252 



BACTERIA IN RELATION TO PLANT DISEASES. 



Substituting asparagin for potassium nitrate, the results shown in table 3 1 were obtained. 

 TABLE 31. Deli Tobacco Organism in Meyer's Solution with i per cent Asparagin and Carbon Foods. 



Glycocoll. B. solanacearum with glycocoll alone does not grow, but it grows on addition of a 

 carbon food such as glucose, maltose, or mannit, although badly in a part of the cultures and not at all 

 with levulose. 



When glycocoll was used as the nitrogen food the results given in table 32 were obtained. 



TABLE 32. Growth of Deli Tobacco Organism in Meyer's Mineral Solution with 

 o.i per cent Glycocoll and the Carbon Foods Named. 



Also here occurred some typical cases of change in ability to ferment. 



Always in sets of 3, grew TgTi in lactose o, in maltose o, in mannit i ; but TgTiTi in lactose 2, 

 in maltose 3, in mannit 3. 



Of 3 cultures from AbTiT t none grew with glycocoll and lactose, while of 3 others inoculated 

 some time later from the same tube all developed. 



In table 33 all the results are united. The figures relate only to the proportion of cultures that 

 grew, not to the intensity of growth: Thus i denotes growth in i to 20 per cent of the cultures; 2, 

 growth in 21 to 40 per cent; 3, growth in 41 to 60 per cent; 4, growth in 61 to 80 per cent; and 5, 

 growth in 8 1 to loo per cent. The fact that these figures differ so widely throws a strong light on the 

 variability of B. solanacearum. 



