PLATE 7 
A. —J, Spinach plant showing blotched appearance due to chlorosis. The juice 
from this plant was not infectious. 2 , Typical fifth-stage blighted plant. The juice 
from this plant was infectious. 3, Healthy plant. (Original.) 
B. — a , Healthy spinach seedling pricked with a flamed needle as a control, b, 
A pot of seedlings inoculated with the virus of spinach-blight 16 days prior to the 
time this photograph was taken. Note the dwarfed condition of the seedlings and the 
decidedly mottled leaves. (Original.) 
