14 
CAROLINE RUMBOLD 
being depressed by the ammonium solutions (counted with the alkaH metals), 
which were injected at this time when comparatively few trees were being 
treated. 
With hardly an exception the rate of intake for the solutions, irrespective 
of whether they were acid, neutral, or alkaline in reaction, was greater 
than for water. The exceptions were -Weak solutions of the ammonium 
compounds, formic acid 1/6000 G. M., chestnut bark extract, canker ex- 
tract, and possibly the colloidal solutions of metals. 
The typical curve of intake reached its highest point the first 24 hours 
after injection, then decreased steadily. 
Figure 4 shows the rate of intake of an equal number of trees injected 
July with acids, alkalies, and water. The alkalies surpassed the acids 
Fig. 3. Graph showing monthly rate of intake of trees injected with water. 
in the first 24 hours, but in the second they dropped one half in quantity, 
and continued to decrease more rapidly than the acids. Because of this 
rapid decrease in the daily intake of the alkali metals, the trees treated with 
these compounds usually were injected once a week. 
Rankin (28) obtained somewhat similar results when injecting chest- 
nut trees with solutions of lithium nitrate, i.e., the greatest intake was 
dufing the first two days and had practically ceased after the fifth and 
sixth days. 
^ The injections of carbon compounds often ran for three weeks without 
