DESCRIPTION OF PLATES. 99 
Pirate VIII. Fig. 1.—Apple root grafts, showing nine kinds of wrapping used in the 
experiments: A, Ordinary unwaxed thread; B, wrapped with thread, then coated 
with grafting Wax; C, cloth wrapping, the outer end of the strip fastened down with 
grafting wax; D, ordinary waxed thr ead; E, thin sheet-rubber strip with the end 
cemented down; Ff, a graft without wrapping; G, waxed paper strip; H, raftia, 
completely covering the union; J, ordinary raflia wrapping. Fig. 2.—Root orafts 
showing excessive callus at the lower blunt end of the scions. “his callus favors 
the entrance of the disease. When planted in an experiment in the greenhouse, 
these root graits all developed crown-gall at the point of formation of callus. 
Pirate IX. Fig. 1.—The stump of an 8-year-old Collins apple tree grown in orchard 1. 
This tree, the largest in the orchard, was diseased with the woolly-knot form of 
hairy-root. Fig. 2.—Apple root grafts and seedlings used in the experiments: A, 
A hand-wrapped root graft; B, a machine-wrapped root graft; C and D, poorly 
fitted root graits; H and F, healthy apple seedlings; G and H, apple seedlings 
diseased with hairy-root. 
PuatE X. Two rowsof Collins apple trees in orchard | at the age of 8 years: A, This row 
was diseased with the hard form of crown-gall when set in the orchard; B, this 
row was healthy when set in the orchard and remained comparatively so until the 
end of the experiment. 
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