262 
RODNEY H. TRUE 
Table V 
Leaching Action of Distilled Water in 24 Hours 
Medium 
Number of roots 
Growth in 24 hrs., 
mm. 
Electrical conductivity X io-4 
10 
4 
0 
II. 2 
2.32 
1-43 
0.82 
Distilled water 
Distilled water 
This result shows that a volume of distilled water to whiqh four 
lupine roots are exposed for 24 hours gains markedly in conductivity 
in comparison with a like volume of the same medium standing under 
like conditions, but containing no roots. The increase in conductivity 
per root is about 0.151 X io~^ in twenty-four hours. When instead 
of four roots ten are present in the medium, the total fall in resistance 
is distinctly greater, indicating the corresponding leaching action of 
the distilled water. It is to be noted also that the rate of increase in 
conductivity per root is about the same as that seen in the series of 
four individuals, viz., about 0.155 X io~^. 
It was next desired to test this same action over longer periods of 
time, in order to ascertain whether the extraction process was con- 
tinued. 
Cultures containing 150 c.c. were set up, containing ten roots, four 
roots, and no roots, in three series, to run for 48 hours and 72 hours, 
respectively. 
Table VI 
Leaching Action of Distilled Water During 48- and 72-HOUR Periods 
Medium 
Duration of 
test, hrs. 
No. of roots 
in culture 
ISt 
24 hrs., mm. 
Growth rate 
2d 
24 hrs,, mm. 
24 hrs., mm. 
Electrical 
conductivity 
at end of 
period X io-4 
Distilled water .... 
48 
10 
4-35 
72 
10 
4.76 
Distilled water. . . . 
48 
4 
2.5 
1.87 
72 
4 
3-0 
2.5 
2.06 
Distilled water. . . . 
48 
0 
0.80 
72 
0 
0.75 
This table shows that both in the cultures containing 4 roots and 
10 roots, respectively, the leaching of ions into distilled water con- 
tinues, but at a slightly diminished rate in comparison with that seen 
in the first 24-hour period, the total leaching for the 48-hour period 
being relatively greater than for the 72-hour period. 
