24 MISCELLANEOUS PAPERS. 
reinfected by careless workmen from the parts not yet treated. Live 
steam under considerable pressure conveyed through parallel lines of 
buried gas pipes and let loose into the soil at short distances by suit- 
able small openings is probably the best method of applying steam. 
It may be applied, however, as Shamel has recommended for seed 
beds, i. e., under large shallow metal pans, which are then moved to a 
fresh portion of the field, and so on until all is treated. <A lettuce 
grower in Boston has invented a sort of drag-tooth device of gas pipe 
which is driven down into the soil and steam turned on for a half hour 
or more. This is then lifted and driven down in another place, and so 
on until the whole bed is covered. It effectually sterilizes the soil, 
but the labor is very considerable. 
(14) Get your neighbors to unite with you in carrying out these 
measures. 
RECAPITULATION. 
The tobacco wilt is due to bacteria. They occur in the diseased 
plants in enormous numbers. They infest the soil and remain alive in 
it a long time. The plants are commonly infected through injuries 
due to nematodes (eelworms) which cause swellings on the roots, or 
through roots broken in setting out. Late transplanting from the 
seed bed is very disastrous when this microorganism is in the soil. 
Potatoes, tomatoes, eggplants, and other members of the nightshade 
family are also subject to this disease. 
Sound plants depend on planting in uninfected land. To keep un- 
infected fields free and to reduce the amount of infectious material in 
diseased fields, remove and burn the diseased plants and practice the 
other hygienic measures here recommended. 
Immediate remedial measures should look to reducing the number 
of nematodes in the soil; to greater care in transplanting, so that the 
plants, and more particularly the roots, shall not be wounded; and 
under tents, if the cost is not prohibitive, to destruction of the bacteria 
by steam heat. 
Remote remedial measures should look to’ breeding up races of 
tobacco, which shall be resistant to this disease either directly or indi- 
rectly by being resistant to root nematodes. 
ATS 0 
