THE INJECTION OF CHEMICALS INTO CHESTNUT TREES 
5 
Sanford (22) published a note on the effect of potassic cyanide on the 
scale. He considered the insertion of the salt beneficial to the tree. This 
result was disputed by Surface (23), Shattuck (24), Moore and Ruggles (25), 
and Flint (26). The experiments of the latter-named workers showed the 
injurious effects of a concentrated solution of cyanide of potassium on plant 
tissues. No attempt was made to try the effect of a gradual impregnation 
with dilute solutions of the salt. These articles are reviewed by Elliott 
(27) in a publication which describes the effect of cyanide of potassium on 
woody and herbaceous plants. Elliott worked with a killing solution, as 
he inserted the crystals under the bark and epidermis of the plants and 
depended on the sap to dissolve the crystals. The reactions of the plants 
were extreme, the tissues in the path of the solution being killed when the 
solution was concentrated. He found that the weathe^ had a decided 
effect on the kind of reaction and the time of response of the tree. Trees 
treated on cool, damp days responded more slowly and showed less extensive 
injury than those treated on hot, dry days. He found also that the rate of 
transpiration affected to some extent the path of the solution. When trans- 
piration was slow the solution passed into the cells surrounding the vessels; 
when it was rapid the solution appeared to pass through the vessels without 
going into the surrounding cells. 
Rankin (28) injected ten chestnut trees with lithium nitrate solutions 
varying from o.i to 0.002 percent. His analysis of the trees showed that the 
salt had penetrated the bark and sapwood above and below the place of 
injection. When trees were less than three inches in diameter there was 
complete penetration of the heartwood, but in trees of greater diameter the 
penetration did not seem to follow a definite rule, the heartwood sometimes 
being impregnated, sometimes not. The tip of the trees was found im- 
pregnated. Aside from blotching of leaves the trees were not injured. 
The Russian and American papers give the most definite reports, both 
as to practical methods of injecting and as to the results of the injection. 
The Problem 
In studying such a problem as the injection of a tree, a number of 
fundamental considerations present themselves: 
A substance in solution injected into a tree generally passes through 
those vessels in the neighborhood of the place of injection through which the 
crude sap ascends from the roots to the leaves. It can also descend through 
those vessels, but in all of this there is lacking that persistent passing and 
returning of a stream such as constantly bathes the cells of the animal 
body. 
The streams passing through this region, besides varying constantly 
in rate of flow, content, concentration, and acidity, are also under different 
atmospheric pressures. 
