Equilibrmm in the Intake of Dyes by Discs of Plant Tissue. 515 
Table III. Absorption of Dye, by living Tissue of other Species, from 
Solutions of Various Concentrations. 
Original 
external concentration 
in per cent . 
Final external concentration in per cent.— 
A T eutral red. Methylene blue. Methyl violet. 
Potato. Artichoke. Turnip. 
o-i 
0-05 
O-OI 
0.005 
0.085 
0.018 
0-0019 
0.0008 
9.04 
0-007 
0-0027 
0.0006 
0-08 
0.03 
0-0025 
0-00 1 
If the relation between the final external concentrations and the final 
1. 
internal concentrations corresponds to the adsorption equation y — kc m , 
where y — final internal concentration, c — final external concentration, and 
ic and m are constants, then the graph obtained by plotting the logarithm of 
Fig. 2. The relation between final internal and final external concentrations in the case of 
living carrot tissue immersed in solutions of neutral red. 
the final external concentration against the logarithm of the final internal 
concentration will approximate to a straight line. This was the case in 
most of the experiments with carrot tissue ; in Figs. 2 and 3 the graphs 
for neutral red and methylene blue are so plotted. In the case of tissues 
other than carrot, however, the results differed somewhat ; Fig. 4 shows 
the graph for neutral red, in which discs of potato tissue were immersed. 
Similar figures were given by the results obtained with artichoke and turnip 
tissue. 
Series 2. Experiments with dead tissue. 
These experiments were carried out with discs of carrot tissue, which 
were killed in a mixture of acetic acid and absolute alcohol ; they were then 
thoroughly washed and transferred to the experimental dye solutions. Two 
sets of experiments were made, one with methylene blue and one with 
methyl violet. The results with methylene blue are summarized in Table IV, 
and the course of absorption is plotted in Fig. 5. 
