598 Williams.—The Influence of Immersion in Certain 
The curves obtained suggest the following possible equations: 
<«> v =-f 
(b) Y = Ae- mx 
In the case of (a) the equation can be written: 
log Y = log A—in log x, or 
log Y — constant — m log x. 
while ( b ) can be written : 
log Y = log A — mx, viz. 
log Y == constant — mx. 
Fig. 2 shows the graphs obtained when logs of the critical times are 
plotted vertically and values of log (C)+ 1 are plotted horizontally, 
(log C) + 1 is used instead of log C merely for convenience, to avoid so great 
a number of negative values. 
It will be seen that for all the substances examined, except barium 
chloride, an approximation to a straight line is obtained for these graphs in 
Fig. 2, suggesting that over the limited periods studied 
log T — constant— A ((log C) + 1), where 
T — time to produce the change in permeability, 
C — concentration in gram-mols per litre. 
Summary. 
1. Immersion in certain solutions of electrolytes was found to produce 
permeability to 0*2 per cent, ferric chloride in cells of ‘London Pride’ 
petioles. 
2. The entrance of the ferric chloride was indicated by its reaction 
with the tannin contained in these cells. 
3. The time of immersion needed to produce the abnormal permeability 
depended upon (a) the concentration employed, (b) the electrolyte chosen. 
4. For aluminium chloride, potassium chloride, potassium nitrate, and 
barium nitrate, results were obtained which suggested approximations to 
the relationship : 
log T — constant — A ((log C) + 1) 
where T — time of immersion needed to render membrane permeable 
to o-2 per cent, ferric chloride, 
C = concentration in gram-mols per litre, 
A = constant depending upon electrolyte used. 
5. Abnormal permeability with regard to the iron chloride could be 
produced without the membrane becoming permeable to a rose-coloured 
material frequent in the sap of the cells. 
