20 MISCELLANEOUS PAPERS. 
SPECIFIC GERM INVOLVED. 
The cultural characters of the tobacco organism are the same as 
those of Bacterium solanacearum derived from tomato or potato, and 
now that good cross-infections have been obtained no doubt remains 
that the Granville wilt of tobacco and the brown-rot ef potato, tomato, 
and eggplant are one and the same disease, i. e., due to the same 
organism, all of these plants belonging to the nightshade family and 
being rather close relatives. The Florida tobacco wilt at Quincy and 
Hinson appears to be the same thing. I examined diseased plants 
from Florida some years ago and again this year. 
The writer formerly stated (1896) that he did not succeed in cross- 
inoculating Bacterium solanacearum into tobacco and peppers, and at 
that time he believed tobacco to be exempt, but not many experiments 
were made, and we may assume either that the cultures used had lost 
their virulence or that the particular plants selected were too old or 
growing too slowly, or for some other reason were unusually resistant. 
The writer now believes that Bacterium solanacearum does frequently 
lose its virulence by continued culture; that, in general, old and slow- 
growing plants are difficult to infect; and that some individuals and 
some varieties are more resistant than others. This, I believe, suffi- 
ciently explains the former failures. We may conclude, therefore, in 
searching for remedies that we have one disease to deal with and not 
several. 
METHOD OF ENTRANCE OF THE BACTERIUM. 
If stomatal infections occur, which is not unlikely, especially in wet 
weather, they have not yet been demonstrated. So far as we know, 
this organism enters the plant only through wounds. Van Breda de 
Haan found the root system especially subject. Stevens and Sackett 
state that the infection is first in the root. A large number of infec- . 
tions undoubtedly take place under ground, the organism present in 
the soil entering the plant through wounds made in transplanting or 
cultivating, or by small animals infesting the soil. Roots broken in 
transplanting and leaves pulled or pinched off at that time are respon- 
sible for many infections, and it would seem that by care the number 
of such wounds inviting infection might be greatly reduced. 
It has been observed in Sumatra, where occurs a destructive bacte- 
rial wilt some years ago identified by Hunger as due to Bacterium 
solunacearum, that the tobacco plants are peculiarly subject to it when 
grown on land infested with eelworms (nematodes) or with insects 
which attack the roots or base of the stems. Rainy weather is favor- 
able to the progress of this disease, although the wilt may be detected 
first in dry weather. In this country it has been observed, especially 
by Earle on tomatoes in Alabama, that wet soil is peculiarly favorable 
to the spread of this disease. All observers agree that the root system 
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