CROWN-ROT OF FRUIT TREES: HISTOLOGICAL STUDIES 485 
appear to have established a close contact with the old wood ; but in 
Fig. 12, representing a section in which the dead zone had not been 
so wide and still contained a few living cells, the new growth is much 
more firmly attached to the old wood. Fig. 13 again is more like 
Figs. 10 and 11, although its dead or injured zones are less extensive; 
in the section here shown, too, some living cells capable of further 
growth appear, which are attached to the old wood and have grown 
outward to meet the growth from the bark. In the tissues shown in 
Figs. 10, II and 12, the initial injuries had been most severe in the 
cambial and inner phloem regions and are of the type shown at the 
left in Fig. i, Plate XXI; while Fig. 13 shows a regenerated condition 
of an initial injury more like that indicated in Figs. 7 and 9, Plate 
XXI, where some living bark cells or cell-groups remain attached to 
the wood. In Fig. 14 is shown an effort toward recovery that is 
rather remarkable and far advanced for May i. This represents a 
reaction to wounds of the type shown near the right in Figs, i, 3, 4, 5 
and 6, Plate XXI. In addition to the general compression of the 
dead tissues by the growth of the living cells around them, many 
proliferating cells have pushed in among the portions of the dead 
sheath, thereby facilitating the re-establishment of living connections 
between the outer bark and the living inner phloem that remains 
attached to the wood-cylinder. Considerable injury also occurred 
in the cambium, although small portions of the latter appear to have 
survived. A new cambium, however, is seen to be forming outside 
among the irregular cells arising from the wound growth. The figure 
does not show it as clearly as the microscope; it is beginning to take 
form in the line cc. Fig. 15 represents a similar instance, except that 
the initial injury was more extensive and that larger groups of dead 
cells resulted. A new cambium is forming at cc, though it is in- 
complete and still has compressed fragments of dead tissue in its 
course. Fig. 16 seems to be a later stage of a case something like the 
left-hand portion of Fig. 8, where the cambium was only slightly 
injured and the outer phloem rather severely, though in more or less 
isolated streaks and patches. Some of the rays are dead, although a 
few are practically normal, like that near the right of Fig. 16. The 
new cambium is quite distinctly indicated by the dense band cc. 
In Fig. 17, comparable but severer initial injuries obtained. The re- 
established living connections between the growing phloem and the 
wood are few and scattered, and the injury in the outer phloem forms 
