THE INJECTION OF CHEMICALS INTO CHESTNUT TREES 
7 
in form, the greatest height being about five meters, the mean height four 
meters. The orchard had never been pruned or cared for other than by 
cutting out the underbrush just before the chestnut harvest each fall. 
In 191 2, when the plots were chosen, they were cleared of underbrush 
and dead infected trees and were kept clear. Such cankers as threatened 
soon to girdle the trees were cut out under sanitary conditions. The re- 
maining cankers on the trees were outlined with paint in order to note their 
rate of growth. The apparatus used in making the injections has been 
described elsewhere (29)^ 
Injections 
Generally two injections were first made in a tree, on opposite sides of 
the trunk. The next two injections were at right angles to the first two, a 
little higher up the tree. If more injections followed they were made still 
higher up in the spaces between the first injections, or on the branches. 
Observations on the trees injected with substances which blotched the 
leaves showed that in this way all the branches on the tree could be reached. 
The hole cut for injection was one centimeter in diameter, and the width of 
two annual rings of wood into the tree's interior. All the records are based 
on the intake through holes of, this size. 
All the substances injected were dissolved in water. This water came 
from a spring in the orchard and was very lightly mineralized.^ 
2 In 1915 a different method of injecting trees was tried. In place of the clamps used 
in the old method, link chains tightened by turnbuckles hold the perforated rubber corks 
against the tree trunk. The corks are protected from the metal chain by iron washers. 
Glass T-tubes thrust through the corks introduce the salt solution into the injection holes. 
The tubes leading from the reservoirs are attached to the vertical ends of the T-tubes, 
The free ends of the horizontal arms of the tubes are tipped by pieces of rubber tubing. 
A tempered steel tube shaped like a laboratory cork borer makes the holes in the trunk. 
It can be driven into the tree through the horizontal arm of the T-tube after the apparatus 
is in place and the solution fills the T-tube. The solution is cut off by a pinch cock placed 
over the end of the rubber tip after the drill has been removed. Glass T-tubes were found 
to be safest for this work because the presence of air bubbles, or leakage in the connections, 
could be detected easily. It is necessary, for a good injection by this method, that no air 
enter the injection hole. Seven injections at a time have been made by this method. 
* Analysis of water by Bureau of Chemistry, Department of Agriculture: 
Mg. per liter 
Silica (SiOa) 5.8 
Sulphuric acid (SO4) 0.8 
Bicarbonic acid (H2CO3) 10.4 
Nitric acid (NO3) 0.5 
Chlorine (CI) 1.5 
Iron (Fe) 0.2 
Aluminum (Al) 0.0 
Calcium (Ca) 1.2 
Magnesium (Mg) 0.9 
Potassium (K) 0.7 
Sodium (Na) 2.0 
The water was tested for heavy metals, lead, copper, etc., none being found. 
