WILT-DISEASES OF TOBACCO. 



251 



like other things, because, in the first place, i per cent glucose is not a poison and second, in an alka- 

 line solution the growth of B. solanacearum is favored. With an eye upon the variability of the Deli 

 strains of B. solanacearum, I must ask once more: Is the difference constant that Uyeda found? 



Of 1 2 Deli strains, 8 showed no growth with asparagin and glucose ; 4 grew badly and for the 

 most part in a portion only of the tubes. Of these 8 strains, 5 were inoculated into tobacco, reiso- 

 lated, and re-tested with asparagin and glucose, whereupon 4 of the 5 grew in part of the cultures. 



These same 8 glucose negative strains were also saccharose-negative, but after 5 strains had been 

 " freshened " by inoculation into tobacco each one of the 5 grew in a part of the cultures set, and also 

 with potassium nitrate the same thing was shown more grew with saccharose than with glucose. In 

 a repetition with saccharose the same result was obtained. 



TABLE 30. Deli Tobacco Organism in Meyer's Solution with 0.25 per cent KN0 3 and Carbon Foods. 



A mmonia Nitrogen. With ammonia nitrogen and with a suitable carbon food the Deli strains of 

 B. solanacearum grew well, as shown by the results with ammonium succinate, lactate, tartrate, and 

 citrate; further by 13 of 21 cultures from 7 sources with ammonia and glucose; and also by the urea 

 cultures (46 of the 52 with glucose and 44 of the 49 with saccharose). 



In acid solution of i per cent ammonium chlorid, B. nicotianae grew for Uyeda and B. solana- 

 cearum did not, or on addition of i per cent glucose only feebly, B. nicotianae also then did not. 



With i per cent ammonium chlorid and i per cent glucose in Meyer's solution, not neutralized, 

 no growth appeared in 17 of the 18 cultures of the Deli tobacco organism from 6 sources, and with 

 i per cent glycerin in none of the 2 1 cultures from 7 sources, although otherwise the growth with 

 glycerin was comparable with that of glucose, but easier. These results harmonize well with Uyeda's 

 when he used acid solutions. Yet after neutralization with NaCOj (litmus neutral) the growth was 

 very strong, as well with glucose as with glycerin. Even when inoculated from old weakened selenit- 

 agar cultures there was still growth with glycerin but no longer with glucose. 



It is thus plain that ammonia nitrogen can be used very well by B. solanacearum,someitiing that 

 is not evident from Uyeda's communications. 



Using Medan III and Florida potato (1914), the writer obtained similar results with these sodium salts, . ., no 

 growth with the lactate, acetate or butyrate, and prompt moderate growth in all of the tubes (8 of each strain), using 

 the malate, tartrate, or succinate. In Meyer's solution with ammonium citrate there was heavy growth, and with am. 

 tartrate and am. succinate, moderate growth (4 days), but none with ammonium lactate (4 days). Both strains 

 grew in Meyer + urea + grape or cane sugar. 



