444 BOTANICAL GAZETTE [DECEMBER 
In direct contrast to these data is the record for water content 
in random soil samples taken from field areas where B. sagittata was 
growing in abundance. Table III shows such sample records, with 
normal and air dry weights. 
TABLE III 
SHOWING PERCENTAGE OF WATER IN RANDOM SAMPLES OF SOIL IN WHICH B. sagittata 
GROWS 
Sample I 2 3 4 5 
Weight in gm........... 94.00 126.42 89.27 104. 26 TIO.02 
Air dry weight.......... 79.11 103.64 77.56 9Q.12 go.03 
Percentage loss......... 15.85 eO:02 2 48.37 4.89 18.18 
Average loss of series, 14.46 per cent. 
Table ITI shows a fluctuation of water content in the soil entirely 
incommensurate with the constant water values of the rootstocks. 
This may be accounted for in part by the size of the soil particles, 
since they, too, are far from uniform, and such differences would 
cause both a difference in weight of soil per unit mass and a con- 
sequent difference in capillarity. The fact remains, however, that 
the plant, irrespective of its root size, selects a relatively constant 
amount of water from soils that differ noticeably in water content. 
Calculations were made also to determine the percentage of 
resin in air dry roots and leaves. The parts selected were first 
weighed, then placed in pure ether in an air-tight compartment. 
They were left in this container for a week, during which time they 
were shaken frequently. This method of extraction was used after 
it had been ascertained that ether was the best solvent for the resin 
of this plant. At the end of this time the ether extract was poured 
off, filtered, and the ether allowed to evaporate at 20° C. until a 
constant weight had been secured.. For roots dug in July the per- 
centage of pure resin amounted to 3.3; for roots dug in October the 
percentage was 3.3; for roots dug in May, some three or four weeks 
after the,new growth had begun, the percentage was 5.2. This 
shows a constant resin value during the resting period and an 
increased resin content for the growing period. The percentage of 
resin found in the leaves was 9.8. This value was found for leaves" 
