ENpDOTHIA CANKER OF CHESTNUT 541 
The latest published information is given by Metcalf (1914:8), who 
reports: “‘ The disease is now generally distributed in native chestnuts 
from Merrimack county, New Hampshire, and Warren county, New York, 
on the north, to Albemarle county, Virginia, on the south. In New 
York the western border of distribution is sharply delimited by an area 
without chestnut trees—a natural ‘immune zone’— which extends south- 
ward along the eastern borders of Fulton, Montgomery, and Schoharie 
counties nearly to the Pennsylvania line in Delaware county. Conse- 
quently, in New York the range of the disease is at present practically 
limited to the valley of the Hudson. In Pennsylvania the western limit 
of general infection is roughly along a curved line extending from the 
northwest corner of Susquehanna county to the eastern border of Clear- 
field county and on to the southwest corner of Fulton county. West of 
this line the advance infections were cut out by the Pennsylvania Chestnut 
Tree Blight Commission. The disease has not yet been found in Ohio 
or Indiana. In general it appears to spread northeastward and south- 
westward, following the direction of the ridges of the Appalachians, much 
more rapidly than westward, across the ridges and valleys. 
“ Scattering infections occur outside of this area. Of these, the out- 
posts are two infections on planted chestnuts in Franklin and Androscoggin 
counties, Maine, and one infection in a nursery in North Carolina. There 
is reason to suppose that the North Carolina infection, and an orchard 
infection in British Columbia, owe their origin to trees imported directly 
from the Orient.” 
The data for the map, Fig. 77, were furnished by Dr. Haven Metcalf, 
and represent the distribution known to him on March 1, 1914. 
One might infer from the above that the disease has been spreading 
in ever-widening circles from the region about New York City. How- 
ever, Clinton (1913:374) remarks: “This apparent wave of progress, 
however, is in part due to a corresponding wave of interest on the part 
of the people to locate a disease so generally discussed.” He, as well 
as many others, believes that the disease has not started from a single 
center, but that other affected localities, such as those in Warren county, 
New York, Bedford county, Virgina, and Lancaster and York counties, 
Pennsylvania, are nearly as old as that about New YorkCity. Even though 
the disease was imported from the Orient, as now seems certain to have been 
the case, it is reasonable to suppose that there were centers of infection 
started at distant places by the shipment of nursery stock. None of 
these outlying centers, however, have developed areas of total destruction 
such as that around New York City; so that it is still reasonable to sup- 
pose, from the evidence at hand, that this was the original center and that 
all other centers were early spot: infections originating from it or from 
later direct importations. 
