86 
Walter Stiles 
A similar influence of concentration of the dye was found with 
potato immersed in neutral red solutions, with artichoke tuber in 
solutions of methylene blue and with turnip root in solutions of 
methyl violet. It will be observed that the absorption ratios are very 
much higher in the case of basic crystalloidal and semi-colloid dyes 
than in the case of the acid eosin and the colloidal, although basic, 
aniline blue, although in both cases the influence of dilution of the 
dye is to bring about an increase in the absorption ratio. Miss Redfem 
has shown that the absorption here also represents approximately 
the relation between concentration and quantity absorbed at equi¬ 
librium. Deviations from this rule may be partly due to the 
approximate character of determinations by the colorimetric method, 
and partly to the complicated nature of the absorption process. 
The dependence of the position of equilibrium on the nature of the 
absorbed substance. We have already noted in the case of dyes that 
the intake of a dye by plant tissue depends very greatly on the nature 
of the dye. In general basic dyes are absorbed to a very much greater 
extent than acid dyes, although this rule is not without exception, 
while among each group of dyes there is considerable range of varia¬ 
tion in the extent of intake. Stiles and Kidd (1919 b) have shown 
the same to be the case with salts. In Table XXXIX are shown the 
absorption ratios they found in the absorption by carrot tissues from 
solutions of a number of chlorides, sulphates, nitrates and potassium 
salts in initially the same equivalent concentration, namely, 0-02 N. 
The results within each group are strictly comparable. 
Table XXXIX 
Absorption Ratios of a Number of Chlorides, Sulphates, Nitrates and 
Potassium Salts presented to Carrot Tissues in a Concentration of 
0*02 N 
Duration of 
experiment 
Absorption 
Group 
Salt 
in hours 
ratio 
I 
Potassium chloride 
9 i 
3*58 
Sodium chloride 
3-49 
Lithium chloride 
1*16 
Calcium chloride 
1-09 
II 
Potassium sulphate 
64*5 
0-51 
Sodium sulphate 
,, 
0-46 
Magnesium sulphate 
,, 
0-097 
III 
Potassium nitrate 
7 X ’5 
4-65 
Sodium nitrate 
3-30 
Calcium nitrate 
1*19 
Aluminium nitrate 
o *53 
IV 
Potassium chloride 
42 
1-99 
Potassium sulphate 
Potassium nitrate 
o *55 
2-20 
