136 
T. G. Hill. 
This being so, various questions arise. What is the effect of 
such differences in the salinity of the soil upon the plants ? How 
does the plant accommodate itself to the fluctuating concentration of 
the soil-water ? What is the osmotic condition of the cells of the 
plants ? 
Hitherto, the chief work on osmosis at Erquy had been carried 
out on the cell-sap of the aerial parts of the characteristic plants 
{Salicornia and Suaeda), and, although the results obtained were of 
interest, they do not afford much information in this particular 
connexion, viz., the osmotic properties of the plants in connexion 
with the variability in the salinity of the soil-water, inasmuch as 
these members are not organs of absorption. For this reason 
attention has been paid to the osmotic properties of the root-hairs, 
which work has been done in the spring-time on seedlings owing to 
the practical impossibility of successfully washing out the soil from 
the roots of mature plants without damaging the regions of the 
active root-hairs. 
The investigation was commenced in April, 1907, and the first 
feature to be investigated was the osmotic equivalent of the cell- 
sap of the root-hairs. 
The following table represents the results;— 
TABLE III. 
Locality. 
Plant. 
Osmotic Equivalent. 
Tansley’s Pan. 1 ... 
Salicornia 
... 6-7% NaCl 
n ... 
... 9 9 • • - 
... 6-73%- „ * 
>5 * * * 
Suaeda 
... 6-7% „ 
J J ... 
... 99 v. • 
... 6-73% „ * 
Station 1 ... 
Salicornia 
... 5-8% „ * 
„ 4 . 
... 99 . . 
6-26% „ * 
,, 4 ... ... 
Suaeda 
6-26% „ * 
Ploughed field ... 
Mesophyte Seedling 2 
1-5% „ * 
These observations were of a preliminary nature : on allowing 
the seedlings to remain bathed in the solutions of sodium chloride 
in serial decreasing concentrations, it was found to be a matter of 
considerable difficulty to determine exactly the osmotic equivalent of 
the root-hairs ; it always appeared slightly lower than the saline 
1 A pear-shaped pan south west of Control-Stations 8 and 9. 
2 In all probability a Composite. 
Results marked thus were obtained by Professor F. W. Oliver 
independently of the writer. 
