On the Influence of Immersion in certain Electrolytes 
upon Cells of Saxifraga umbrosa. 
BY 
MAUD WILLIAMS, B.Sc. 
With three Figures in the Text. 
I N earlier work (1) upon this subject strips from the upper side of the 
leaf-stalk of Saxifraga umbrosa were immersed in electrolytes of known 
concentrations and the times of immersion required to produce a certain 
arbitrary change determined. The cells in question are rich in tannin, 
and over a long period are impermeable to weak ferric chloride solution, so 
that undamaged cells do not show the blue coloration due to reaction of 
tannin and iron chloride when the sections are mounted in the latter solution. 
When, however, immersion in the electrolytes studied had been prolonged 
sufficiently the nature of the protoplasm was found to be so modified that 
the ferric chloride diffused it, and it was possible to obtain blue tinting and 
later a precipitate. In the experiments already recorded immersion in the 
electrolyte was continued until it was found possible to produce the ferric 
chloride reaction (using o*a per cent.) when the sections were soaked in the 
reagent for three minutes. 
The experiments showed that all the solutions studied produced this 
change if the time of immersion were sufficiently prolonged, and there was 
evidence for a definite connexion between time required and the concentra- 
tion employed. Over the limited range of time and concentration it 
appeared that the following formula held for a particular electrolyte : 
log T + k (log C + 1) = constant 
where T = time required, 
C = concentration in gram-mols. per litre, 
and the constant depended upon the electrolyte. 
These experiments were open to criticism from several points 
of view. 
i. The experiments had been carried out at room temperature and no 
corrections were possible for fluctuations. 
2. It had not been determined whether the change in the protoplasm 
was of a reversible nature or whether permanent injury had resulted. 
3. The effect of the ferric chloride upon the protoplasm had not been 
studied beyond the fact that the solution alone took several hours to enter 
[Annals of Botany, Vol. XXXVI. No. CXLIV. October, 1922.] 
