THE INJECTION OF CHEMICALS INTO CHESTNUT TREES 1 3 
organic compounds, and water. As the number of trees being injected 
varied from month to month, these curves simply approximate the rate of 
intake. 
93 trees are represented in the curves of the hydrocarbon derivatives of 
Fig. 2. Graph showing monthly rate of intake of trees injected with the alkaH metals. 
the benzene series: 7 trees in April, 17 trees in May, 26 trees in June, 33 
trees in July, and 10 trees in August. The curve for May, for instance, 
represents more than 17 injections, for, as has been explained (p. 7), two 
injections were made in a tree on opposite sides of the trunk, and the daily 
amount of intake of an injected tree was the mean intake through two 
injection holes. In May it happened that many of the injections continued 
for two and three weeks. (The more readily the solution flowed into the 
tree the fewer were the reinjections.) A number of the trees were injected 
during one month only, very few for three months, so that no comparison 
between the intake of a solution by a single tree in the different months 
could be made. For these reasons the curves approximate the rate of in- 
take, as has been previously stated. 
The curves representing the alkali metals are better representations 
because more trees (121) are represented: 9 in April, 8 in May, 9 in June, 
26 in July, 33 in August, 30 in September, and 17 in October. Not only 
are more trees represented, but more injections to a tree. In spite of the 
large number of trees, the curves for April, May and June are not typical, 
