Permeability 85 
This equation may be written in the form i = ke m , and this is 
the adsorption equation. (See Chapter 111.) 
Although this result does not prove that the intake of salts into 
the cell is a process of adsorption of the salt by a constituent of the 
cell, it indicates that this is a possibility. But the results do give 
clear proof that the absorption of salt by carrot root does not proceed 
until there is equality of concentration inside and outside the cell. 
With lower concentrations there is heaping up of salt inside the cell, 
while with higher concentrations the absorption ratio is less than unity. 
That this is connected with the living condition of the cells is evident 
from the fact that with dead tissue the absorption ratio approximates 
to unity as shown by Meurer’s results already cited, and by the result 
obtained with dead carrot tissue in 0-02 N sodium chloride by Stiles 
and Kidd. The absorption ratio found with such dead tissue was 
o*88, whereas living tissue under otherwise exactly similar con¬ 
ditions yielded an absorption ratio of 3-5. 
This work has been extended by Miss Redfern (1922 b) to the 
uptake of dyes, the same tissue, carrot root, being for the most part 
employed. The dyes used were neutral red, methylene blue, methyl 
violet, aniline blue, eosin and congo red. The absorption ratios found 
with these dyes presented in various concentrations (initially o-i, 
0*05, o-oi and 0-005 P er cent.) are shown in Table XXXVIII. 
Table XXXVIII 
Absorption ratio at equilibrium in the absorption of various dyes 
by disks of storage tissue. (Data from Redfern) 
Concentration at equilibrium 
_ 
- 
Absorption 
Dye 
Character of dye 
External 
Internal 
ratio 
Neutral red 
Basic; semi-colloid 
o-o 6 
2-0 
33*3 
0-03 
i-o 
33-3 
0-0005 
o -475 
950 
0-000125 
0-244 
1952 
Methylene blue 
Basic; crystalloid 
0-032 
3-4 
106 
o-oi 
1-9 
190 
0-0008 
0-46 
575 
0-0003 
0-235 
783 
Methyl violet 
Basic; semi-colloid 
0-03 
3*5 
117 
o-oi 
2-0 
200 
0-0018 
0-41 
228 
o-ooi 
0-20 
200 
Aniline blue 
Basic; colloid 
o-i 
— 
— 
0-045 
0-25 
5-56 
0-008 
O-I 
12-5 
0-003 
o-i 
33-3 
Eosin 
Acid; crystalloid 
o-i 
— 
— 
0-045 
0-25 
5-56 
0-0085 
0-075 
8-82 
0-004 
0-05 
12-5 
