80 TRANSACTIONS OF THE 
TABLE III. 
Effect Produced on Growth of Plants by Sterilizing 
the Water in Which They are Grown. 
—<$<$_§___. 
| 
Ca) Medium | Condition of Green Wt. of | Dry Wt. of 
0. | medium tops in gms. | roots in gms 
— 
1s} Dist. BOO | Unrenewed | 1.55 | 141 
2 | Dist. H,O | Renewed 1.65 SEX) 
3.6 (4) Dist. HO | Sterilized , | 2.40 | 225 
4 oes H ,O | Sterilized 3.05 | 233 
| SD ree en 
was due to the destruction of the bacterial and fungous 
floras of the medium, to a decomposition of any 
contained toxic substances, or to incidental effects such 
as aeration of the water by the boiling process, was not 
definitely determined. All things carefully considered, 
however, the stronger line of evidence seems to favor 
the first-mentioned hypothesis. 
The results of the conductivity experiments were 
both interesting and enlightening. The first point that was 
definitely determined was that there was much greater 
total and permanent excretion of electrolytes from the 
plants in the renewed than in the unrenewed distilled 
water. Table IV shows this result. The reading on the 
Wheatstone bridge for distilled water only was approxi- 
mately 6.0. That figure is then considered the starting 
point for the conductivity readings for exosmosis, and 
the values given represent the readings on the bridge. 
(See Table IV.) 
Another point of interest was the reabsorption of 
electrolytes—as seen by the decrease in conductivity of 
the medium—in those cultures in which the distilled water 
was not renewed. This phenomenon was also fre- 
quently observed to be characteristic of normal, healthy 
peas when transferred from full nutrient solution to dis- 
tilled water. There would be considerable exosmosis 
but after one or two days reabsorption would occur. 
Conductivity readings of the distilled water medium 
