Electrolytes ttpon Cells of Saxifraga umbrosa. 
575 
Summary. 
1. Experiments upon changes produced in cells of Saxifraga umbrosa 
by immersion in certain electrolytes have been repeated and extended. 
Times of immersion necessary to produce a certain arbitrary change, viz. 
permeability to o-i per cent. K 2 Cr 2 0 7 , have been found for different 
concentrations of various salts. 
2. The change of permeability referred to in this and earlier work has 
been shown to be irreversible and to indicate damage to or 4 poisoning ’ of 
the cell. 
3. The importance of immersion experiments at a fixed temperature 
has been shown. 
4. The equation log T+k (log C+i) — K, 
where T — time of immersion needed to produce the change, 
C — concentration in gram-mols. per litre, 
has been shown to hold in the cases examined for periods up to four hours 
for immersions at 25 0 C. 
5. This equation obtained for vegetative cells of an angiosperm 
poisoned by immersion in solutions of sodium and potassium salts has 
been found to agree in form with that obtained by other workers for 
disinfection of bacteria and for poisoning of Chlamydomonas by other 
chemicals. 
6. The constant K and the coefficient k depend upon the salt used, 
and equi molecular solutions do not produce equal effects. Evidence is 
put forward in favour of the view that the action of the strong solutions 
employed is connected with the adsorption of ions and consequent pre- 
cipitation of colloidal matter. 
7. The need for study of the action of one kind of charge alone is 
shown and the suggestion made that the investigation of the action of the 
/ 3 -rays of radium may throw light upon the course of events. 
In conclusion, the writer wishes to express her sincere thanks to 
Professor W. Stiles for certain references, to Sir Archibald Reid, K.B.E., 
C.M.G., for his generous loan of a large amount of radium for the present 
experiments, and to Mr. F. J. Harlow, in whose department the work has 
been carried out, for his kindness in arranging for the necessary apparatus 
and for his invaluable advice and criticism throughout the experiments. 
The Sir John Cass Institute. 
