c 209 
twig, or dead area of some kind on the bark, apparently not 
killed by the fungus, from which the infection appeared to spread. 
The end of the branch being killed, dead spots are sure to appear 
lower down, from lack of food, and the spores washed down by 
the rain find easy entrance. Thus it frequently happens that a 
small infected branch will often lead to a serious infection of the 
main stem even before the fungus has had time to grow down 
the whole length of the branch. 
In the case of large branches, the ends of which are killed, 
one side of the branch may entirely die, thus affording an easy 
and speedy entrance of the fungus directly into the trunk. It is 
on this account that pruning large infected branches often fails of 
success. 
In this connection it may be interesting to give a brief outline 
of the results of the infection experiments with young trees in the 
propagating houses mentioned in my former article. In one set 
of experiments, the fungus, taken from pure cultures, was intro- 
duced through wounds into the living tissues of the branch. As 
may be seen from the accompanying illustrations, the branches 
thus infected have all died. An attempt was made in another 
set of experiments to infect young twigs and unfolding buds 
without removing the cortex. No infections of this kind were 
successful. Other infections were made upon the cut ends of 
branches and the progress of the disease down the branch toward 
the trunk observed. A number of check trees were kept in each 
case and they have all remained perfectly sound. 
Interesting observations were also made on the progress of the 
disease during the summer in young trees in the nursery outside. 
One of these in particular was mentioned and figured in the June 
JournaL. ‘A comparison of the condition of the tree early in May 
with its condition now, as seen in the accompanying illustration, 
will show how rapid and how deadly the work of this fungus 
may be. 
I have no treatment to suggest further than the preventive 
measures already mentioned. I realize the extent of the calamity 
in New Jersey, Maryland, Virginia, and other states where’ the 
disease is known to occur, if it is as virulent as it is with us. 
