264 
RODNEY H. TRUE 
the absorption of such by the roots, each culture container received a 
new set of seedlings at the end of each three days. This period was 
chosen since, judging by the growth rate and appearance, it was 
deemed as long a period as lupine roots could be relied upon to survive 
the action of distilled water. Post mortem leaching was expressly 
avoided since it would greatly complicate the situation. Conductivity 
readings were made at the end of each 72-hour interval. In the case 
of the check cultures of distilled water and of Potomac water in which 
no plants were placed, the first readings given represent the conduc- 
tivity of these latter waters at the beginning of the experiment. 
The general features of the result stand out clearly. As the 
distilled water continues to receive the successive lots of roots the 
leaching of these structures continues throughout the experiment, 
as is shown by the steadily increasing electrical conductivity. 
The conductivity of the culture containing 10 roots rises more 
rapidly than that containing 4 roots. At the close of the experimental 
period of 21 days the conductivities representing the total result of 
the changes of each culture were as follows: The check containing no 
roots had risen from a conductivity of 0.87 X iQ-^ to 1. 61 X io~^ 
or in terms of the equivalent concentrations of KCl from o.87ikf/45,500 
to i.6iikf/45,5oo, an increase of o.74ikf/45,500 KCl. The culture con- 
taining 4 roots showed an increase in conductivity from 0.87 X io~^ 
seen in the water before receiving the plants to 7.4 X io~^ correspond- 
ing to a change from 0.87^/45,500 to 7.4ikf/45,500, an increase of 
6.53ikf/45.5oo KCl. Since during this interval the check attained a 
conductivity of i.6iikf/45,500 from sources apart from the plants, the 
roots had contributed the equivalent of 5.81f/45,500 KCl to the solu- 
tion, or about 1.451^/45,500 KCl per root. The culture containing 
10 roots showed a change in conductivity from o.87ikf/45,500 to 
i2.9ikf/45,5oo, a total gain due to the roots of ii.3ikr/45,500 KCl, or 
about I .i3lf/45,5oo per root. It will be noted that the leaching process 
seems to have been somewhat less active in the culture containing 
the larger number of roots than in that containing the smaller number. 
The plants in the Potomac water check series absorbed electrolytes 
throughout the entire period of the experiment, and before the close 
of the interval of observation the river water culture containing 10 
roots contained a less quantity of electrolytes than either of the dis- 
tilled water cultures at the same time and the Potomac culture con- 
taining 4 roots contained approximately the same quantity of electro- 
