6 
CAROLINE RUMBOLD 
The physical attributes of the cells must be considered. The surface 
of the cell walls, aside from the semipermeable membranes of the living 
cells in the region of the vessels, offer surface films which are constantly 
within the field of absorptive and adsorptive forces. 
The chemical content of the sap may be changed by the injections, 
insoluble mineral compounds may be formed and toxins made harmless 
thereby. 
These conditions at this stage of experimentation called for a great 
deal of empirical experimental work with chestnut trees. 
In order to study this subject fundamentally, an attempt was made to 
answer by means of experimentation the following questions: (i) What sub- 
stances can be injected into living chestnut trees? (2) When can they be 
injected? (3) Where does the injected material go? (4) What is the effect 
on the chestnut tree? (5) What is the effect on the fungus growing parasiti- 
cally on the trees? 
The present record gives the results of five years' experimental work. 
The work here reported is not complete. The propositions offered for 
solution have, however, been so varied in character that it seemed proper 
to bring together in this and a succeeding paper the different results so far 
secured, since this work must for the present be laid aside. 
The principal experimental plots of trees were in the center of a blight- 
infected chestnut orchard of some three hundred-odd acres' extent, located 
in southeastern Pennsylvania. They were on top of a hill about 500 feet 
above sea level. This region is hilly and originally was covered by a mixed 
forest of conifers and deciduous trees, a large proportion of the deciduous 
trees being chestnuts. The fact that this is the fourth generation of chestnut 
trees growing here since the Revolutionary War shows how favorable is this 
region to the growth of chestnut.^ 
The trees used in the experiments were orchard trees, for the most part 
Paragon scions grafted on native chestnut stock, Castanea dentata. The 
trees in the plots varied in age according to the year of grafting. One set 
was about ten, the other fourteen years old. They were short, stocky trees 
2 An analysis for alkali content was made of the soil by the Bureau of Soils, Department 
of Agriculture. 
Experimental Procedure 
Experimental Plots 
Trees 
K2O. 
CaO. 
MgO 
P2O5. 
N. .. 
0.08% 
. . trace 
0.27% No CO2 from carbonates. 
0.68% 
trace 
Li 
none 
