WILT-DISEASES OF TOBACCO. 



259 



Micrococcus luteus Lehm. and Neum., Micrococcus pyogenes albus (Rosenbach) Lehm. and Neum., Micrococcus 

 pyogenes {M. bicolor Zimmerman), Bacterium medanense n. sp., Bacterium stalactitigenes n. sp., Bacterium langkatense 

 n. sp., Bacterium deliense n. sp., Bacterium shuffneri n. sp., Bacterium zinnoides n. sp., Bacterium sumatranum n. sp., 

 Bacterium patelliforme n. sp., Bacterium aurantium roseum n. sp., Bacterium rangiferinum n. sp., Bacillus mycoides Fliigge, 

 Bacillus mesentericus, and Corynebacterium piriforme n. sp. These generic names are used in the manner of Lehmann 

 and Neumann, some of the forms being non-flagellate, others polar-flagellate, and others peritriehiate. 



The most interesting discovery recorded is that of the inhibiting action of some of these 

 saprophytes, c. g., B. mycoides, and especially B. mesentericus, on the growth of Bad. 

 solanacearum (fig. 134). The following is an abstract of Honing's last paper. 



(I I) HOW SHALL ONE OBTAIN A RACE OF TOBACCO THAT IS IMMUNE TO THE SLIME-DISEASE? 



Probably the application of some form of selection in tobacco-culture in Deli is as old 

 as the culture itself. The founder of the industry, Nienhuijs, had seed imported from 

 Java, Cuba, and elsewhere, and selected that which gave the best results on the new soil. 

 Obviously he selected with a practised eye and lucky hand: A valuable new variety, the 

 Deli tobacco, being the result. No one knows the age of Deli tobacco in its present form. 

 Perhaps it is the result of one or 

 more accidental crossings among the 

 sorts imported into Deli; perhaps it 

 originated through a splitting 

 caused or not by crossings in Deli 

 whereby arose combinations of char- 

 acters which the first Deli plants 

 really owe to crossings that took 

 place years before in Java or Cuba. 

 Perhaps, also, the new type arose 

 suddenly or by degrees through ex- 

 ternal conditions, which in Deli differ 

 from those of the original habitats. 

 Of this we know nothing, and prob- 

 ably never shall be able to determine. 

 A similar ignorance concerning the 

 time and manner of origin of varieties 

 is, alas, the rule. Of almost all culti- 

 vated plants having a great number 

 of known varieties, the origin lies in 

 the dark, and only of forms which 

 have been isolated in recent years does 

 one know a part of their history. 



Only this is certain: In Deli a 

 variety has arisen which did not previously occur in the older tobacco lands and is not found 

 there at present, unless introduced from Deli. Wherever Deli tobacco grows outside of 

 Sumatra: in Java, the United States, Cuba, Hawaii, everywhere one speaks of Sumatra 

 tobacco, which would not be the case if, in the older tobacco districts, the Deli form had 

 been recognized as a variety indigenous there. Had such been the case, so much trouble 

 would not have been taken on all sides to make the variety nourish. 



Thanks to the favorable results in the years 191 1 and 191 2, one hears less said now than 

 was the case three or four years ago, regarding the degeneration of the Deli tobacco. For 



*Fig. 134. Drawing of a Petri-dish agar-poured-plate showing the inhibiting action of Bacillus mesentericus on the 

 Sumatra tobacco bacterium. This experiment was made as follows: The letter A was painted on the bottom of the 

 dish with a spore-bearing culture of Bacillus mesentericus. When this was dry it did not show. A tube of melted agar 

 was then inoculated heavily with Bacterium solanacearum and poured into the dish. After some days, the letter A 

 appeared and some surface colonies of Bacillus mesentericus which were derived from bacteria flooded from the letter A 

 at the time the plate was poured. Bacterium solanacearum has also grown, but only at a distance from the former. 

 The legends are: i, Bacterium solanacearum; 2, Bottom growth of Bacillus mesentericus; 3, Surface growth of Bacillus 

 mesentericus. (After Honing.) 





Fig. 134.* 



