WILT-DISEASES OF TOBACCO. 



253 



TAHI.E 33. Growth of Deli Cultures of B. solanacearum in Meyer's Mineral Solution with Different 



Carbon and Nitrogen Compounds. 



"' T ammonium compound in the fourth column with Nil 



Honing summarizes his conclusions as follows: 



1. Bacillus solanacearum Smith often loses its virulence quickly. 



2. This loss makes its appearance not all at once, but gradually, first toward Capsicum annuum, later toward Nico- 

 liana tabacum, and finally for Solatium melongena and .V. lycopersicum. 



3. These circumstances explain the contradiction in the papers of Smith and Uyeda. 



4. In Deli up to this time the bacteria have been found by me in: Nicotiana tabacum, Physalis angulata, Indigofera 

 arreeta, Arachis hypogaea, Mucuna sp. ( Acalypha bahmerioides, Ageratum conyzoides, Blumea balsamifera, Synedrtlla 

 nodiftora. 



5. As the result of artificial inoculation the following have also become diseased: Sesamum orientate, Solatium 

 tuberosum, S. lycopersicum, S, melongena, and Capsicum annuum. 



6. Both in its morphological and in its physiological characters the variability of B. solanacearum is much greater 

 than is at present supposed. 



7. In cultures with glycocoll and glucose the bacteria form threads more than 40 cells long, which are mostly 

 crooked, and here and there show strongly swollen, feebly-staining cells without at first showing loss of virulence. By 

 inoculation from these cultures into bouillon the normal growth in the form of single and paired rods returns. 



8. Thus far the Deli strains have formed neither capsules nor spores. For the existence of spores Uyeda has not 

 offered the least proof. 



9. The Deli strains show polar staining after fixation in alcohol or in the flame, and staining with carbol fuchsin, or 

 water solution of methylene blue. When peptone is used the polar staining becomes indistinct or may disappear 

 altogether. 



10. Examined on a slide at the same time with B. colt communis and Diplococcus enteritis, the Deli strains are Gram- 

 negative. 



n. The reduction of nitrate by B. solanacearum (and probably also by other bacteria) can not be studied using 

 starch as a carbon food. 



12. Sodium selenite interferes with the growth to a high degree, or even sometimes stops it altogether on addition 

 of o.i per cent in peptone-bouillon-agar, but is less harmful with o.oi per cent. The selenite is reduced. 



13. The different results reached by Smith and by Uyeda when the organism is grown in milk may be partly 

 explained: a, by difference in the bacterial strains; b, by difference in the age of the cultures; c, very probably by differ- 

 ence in the composition of the milk. 



Because Uyeda in his complete paper announces a different conclusion concerning the milk cultures than in his 

 preliminary communication, and because the behavior of the Deli strains is rather variable, one can ascribe no great 

 worth to the discovered differences. 



14. The trials with fresh milk show that coagulation takes place only rarely (4 out of 95 cultures) and that the 

 reaction is feebly alkalin or neutral. 



With European milk in tins or flasks the reaction after 3 to 7 days is always alkaline. In most of the strains the 

 reaction changed again 3 to 7 days later and the milk curdled. When inoculated from old weak cultures the reaction 

 remained atkalin. 



15. The tests with combinations of different carbon and nitrogen compounds sometimes gave constant results and 

 sometimes variable ones, the latter even when inoculated out of one and the same culture. 



16. Of the 18 substances containing both carbon and nitrogen sources, growth occurred only with tyrosine.pepton, 

 ammonia, ammonium succinate, ammonium lactate, ammonium tartrate, and ammonium citrate, and in a few cases 

 also with asparagin (7 of the 62 cultures, and the 7 belonging to 3 strains). 



17. The following may serve as sources of nitrogen: asparagin, glycocoll, potassium nitrate, potassium nitrite, and 

 ammonia. 



18. As sources of carbon in the combinations tested the following are absolutely unusable: glycogen, starch, 

 lichenin, sodium acetate, sodium butyrate. 



