CHESTNUT BARK DISEASE, 443 
bark -disease, in those regions or states where it has not yet 
obtained a serious foothold, by means of quarantine and cutting 
out all diseased trees. This recommendation was based on the 
results of some experiments carried on in the vicinity of Wash- 
ington, D. C., concerning which they write as follows: 
“Fortunately, however, there is a method of dealing with the 
situation which is applicable to the country as a whole and 
which, so far as tested, is practicable. Early in the course of 
the writers’ investigations it became evident that the disease 
advances but slowly in a solid line, but instead spreads from 
isolated centers of infection often many miles in advance of 
the main line of disease. * * * It therefore seems probable 
that if these advance infections could be located at a reasonably 
early stage, they could be eliminated at relatively little expense, 
thus preventing further spread from these points, at least. 
Accordingly the country within approximately thirty-five miles of 
Washington, D. C., was chosen in the fall of 1908 as preliminary 
territory in which to test this method of control. This section 
has been gone over fairly thoroughly once a year. As will be 
shown by Figure 1, fourteen points of infection were located 
and the infected trees destroyed. Most of this work was done 
by the senior writer. The largest infection was a group of 
nursery trees that had been imported from New Jersey; the 
smallest, a simple lesion on a small branch of a large forest 
tree. In one case eleven forest trees in a group were infected, 
the original infection having been on two trees dating apparently 
from as early as 1907. Up to the present time (June, 1911) 
the disease has not reappeared at any point where eliminated, 
and’ the country within a radius of approximately thirty-five 
miles from Washington is apparently free from the bark disease, 
although new infections must be looked for as long as the 
disease remains elsewhere unchecked. It is therefore believed 
that this method of attack will prove equally practicable in other 
localities, and if carried out on a large scale, will result ultimately 
in the control of the bark disease.” 
Stewart, of the Geneva, N. Y., Station, and the writer, through 
the kindness of Metcalf, had the opportunity of examining, in 
January, 1912, part of the region where this work was carried 
on. Stewart (70) in his paper at Harrisburg said: “I hold 
that no definite conclusions can be drawn from that test.” The 
