54 
CAROLINE RUMBOLD 
The Effect of the Injected Chemicals on the Fungus 
Endothia parasitica 
The results of the injections on the growth of the chestnut bhght canker 
on the chestnut tree have been so uncertain and varied that, were it not for 
the fact that the work must stop for the present, no results would be men- 
tioned. 
It seems best to give a history of the results as they presented themselves. 
The first indication of an effect from the injected chemicals on the 
fungus was in the summer of 191 3. The trees which had been injected 
in 1912 had been inoculated with the chestnut blight fungus in the fall. 
The fungous growth from these inoculations on those trees injected with 
alkali metals had an abnormal appearance. However, the fungus continued 
to grow and eventually killed the trees. This abnormal appearance of the 
fungus together with the fact that the alkali-injected trees had, as a whole, 
a thrifty look led to the decision to put more emphasis upon the injection of 
the alkali metals. 
In 1914, measurements were made of the cankers caused by the inocula- 
tions of 1 913. These showed that the cankers on the control trees averaged 
the same size as those on the alkali-injected trees. The measurements of 
the cankers on the other injected trees gave confused results. As a whole 
the injected trees had larger cankers than the uninjected. 
In 1 91 5, a dead canker was noticed on a tree, no. 185 E, which had 
been injected with lithium hydroxide in April, May, and June, 1913, and in 
June and July, 1914. The dead canker was not noticed at first for the 
reason that dead bark covered the area (PI. IV, fig. A). Not until this 
bark was removed (as one would remove the scab from a healed wound) 
was it noticed that a healthy callus had cut out the cankerous growth 
(fig. B). This same effect was noticed on a tree injected with sodium 
carbonate and on a thymol-injected tree. In 1916 these trees again became 
infected, and in 191 7 the new chestnut blight cankers on them were growing 
at the normal rate. 
In the meantime a better method of injecting the trees had been devised 
(PI. IV, fig. C). Injections were made on forest trees as well as on small 
orchard trees. 
In 1916 the injections were made with lithium and sodium salts only. 
The injections were made in three different regions. One set of trees was 
injected in April, May, and June, the second in June, July, and August, 
the third in August, September, and October. The results of these injec- 
tions showed in 191 7 that sodium salts were not as effective as lithium salts. 
The lithium injections made in April, May, and June seemed to have the 
greatest effect, in that the cankers were not growing vigorously and the trees 
had started to form a callus about the diseased areas. All the check trees 
were dead at the time of the inspection. Those injections made in August, 
September, and October appeared to have had the least effect. In no case 
