52 caroline rumbold 
Effect on Fruits 
All the injected trees with the exception of those treated with the 
concentrated solutions of the heavy metals and formaldehyde produced a 
normal appearing crop of nuts. 
There was no sign of a stimulation of the trees by the substances injected 
further than that the nuts growing on trees treated with the alkali metals 
in general appeared somewhat larger and glossier than those on trees injected 
with water or carbon compounds. Lithium was found in the nuts gathered 
from the trees injected with the lithium salts. The contents of the nuts 
gathered from the other injected trees were not tested further than by a 
superficial feeding experiment with white rats^ to test their possible poison- 
ous effect. In view of the fact that lithium was found in the nuts, it seemed 
possible that some of the other injected substances had found their way into 
the fruits. The amount of poison in them must have been extremely small 
since they did not appear to injure the rats' health. Another indication of 
this lack of toxicity was a count made of the wormy nuts gathered from 
treated and untreated trees in the orchard. This count showed the per- 
centage of wormy nuts to be the same for both classes of trees. 
It seems possible, judging from the varying results of the injections 
made in the spring and fall, that the amount of injected substance which 
finally reaches the nuts can be influenced by the time of injection. The 
late summer injections quickly affected the chestnut fruits, as shown by the 
spotting of the burs and neighboring leaves when injected with lithium. 
For the sake of brevity the substances injected are arranged as carefully 
as possible in groups according to the effect they produced on the trees 
during the summers of experimentation. Very often the trees did not 
respond in the same degree to injections of the same chemical so that it was 
difficult to judge its general effect, and possibly some of these dilutions of 
chemicals could be put in two groups. 
No apparent ejfect on trees 
Water 
Water extract of healthy chestnut 
tree bark 
Congo red 1/40 percent 
Trypan blue 1/40 percent 
Colloidal cuprous hydroxide 1/3300 
CM. 
Colloidal metallic silver 1/6400 CM. 
Methyl alcohol i/ioo CM. 
Acetic acid 1/3000 CM. 
Formic acid 1/6000 CM. 
Lactic acid i/iooo, 1/2000 CM. 
Anilin sulphate i/iooo CM. 
Sodium carbolate i/iooo CM. 
Phenol Sodique, i cc. to 1000 cc. H2O 
Para-nitro-phenol i/ioooo CM. 
Para-cresol i/iooo CM. 
Thymol 1/3000 CM. 
Oil of bitter almonds i/ioooo CM. 
5 Chestnuts were gathered from each injected tree and kept separate in labeled paper 
bags. Twelve rats were fed regularly with the chestnuts. A day of chestnut feeding (the 
nuts for the day being those gathered from trees injected with a particular chemical) 
alternated with one of bread, milk, and grain. 
