88 
Walter Stiles 
conductivity method already described. These investigations yielded 
information on (i) the influence of concentration on the rate of intake 
of salts, (2) the dependence of the rate of absorption on the nature 
of the salt, and (3) the course of absorption in general. Some informa¬ 
tion on these questions and on the influence of temperature, light and 
wounding on the absorption of dissolved substances is also available 
from other sources. 
Influence of concentration. This was investigated for the case of 
a number of chlorides; namely, those of potassium, sodium and 
calcium, the salts being used in concentrations of o-iiV, 0-02 N, 
0-002 N and 0-0002 N in each case. The data obtained with each salt 
are all strictly comparable with each other, the disks of tissue 
employed being all from one batch. 
The actual measurements obtained in the case of carrot are shown 
for the three salts in Table XLI and the results for potassium chloride 
are recorded graphically in Fig. 14, where the relative absorption 
has been assumed proportional to the sum of the fall in conductivity 
of the solution and the rise in conductivity of the same quantity of 
distilled water containing the same quantity of the same tissue. 
Table XLI 
Changes in Electrical Conductivity of Solutions of Various Chlorides 
of Different Concentrations containing Carrot Tissue (40 Disks of 
Carrot, i*8 cm. in diameter and 1 mm. thick, immersed in 100 c.c. of 
each Solution). (Data from Stiles and Kidd) 
Change in conductance of external solution 
Time ,-^ 
Salt 
in 
hours 
Distilled 
water 
0-0002 N 
0-002 N 
0-02 N 
o-i N 
Potassium 
o -5 
_ 
_ 
- 3 
- 167 
- 610 
chloride 
6-o 
+ 80 
+ 58 
- 48 
- 372 
- 970 
24-0 
+ 145 
4 - 92 
-196 
- 892 
-1600 
52-0 
+196 
+ 137 
-223 
- 992 
-1850 
Sodium 
3 -o 
+ 36 
+ 30 
+ 18 
- 113 
- 560 
chloride 
34 '° 
+ 87 
+ 57 
-124 
- 476 
- 1070 
4 i -5 
+ 66 
+ 19 
- 287 
- 885 
-1580 
48-0 
+ 58 
+ 2 
-340 
- 1020 
-1720 
Calcium 
o -5 
— 
— 
+ 3 
- 71 
- 343 
chloride 
I 4'5 
+ 64 
+ 35 
- 53 
- 145 
- 457 
20-5 
+ 86 
+ 53 
- 57 
- 125 
- 37 ° 
36-25 
+ 60 
+ 17 
-105 
- I8l 
- 503 
42'5 
+ 54 
+ 8 
-116 
- 195 
- 47 ° 
It is very clear from these tables and figures that the rate of 
absorption of salt is dependent on the concentration of the salt, the 
greater the concentration the more rapid the absorption. Similar 
