140 
Walter Stiles 
alga underwent a peculiar and characteristic contraction in solutions 
of barium chloride as dilute as o-oooi M. Strontium chloride pro¬ 
duced the same contraction in concentrations of o-ooi M and up¬ 
wards. Chien (1917) found the same contraction could be produced 
with cerium chloride in a concentration of 0*00005 M, in a large 
species of Spirogyra, but not in a small one. In the smaller species 
it was found that the effect of barium chloride was inhibited by 
addition of calcium chloride or cerium chloride to the solution in 
the correct proportions, but that no antagonism could be observed 
between barium and strontium. 
A plasmolytic method has been used by Osterhout (1911, 1912 c, 
1913 b). It was found that cells of a species of Spirogyra were just 
plasmolysed in 0*2 M calcium chloride and in 0*38 M sodium chloride, 
but were not plasmolysed in 0*195 M calcium chloride nor in 0*375 M 
sodium chloride. However, the solution obtained on mixing 10 
volumes of the 0*375 M sodium chloride solution with 1 volume of 
the 0*195 M calcium chloride solution at once brought about plasmo- 
lysis. The failure of the solutions of the single salts in these concen¬ 
trations to bring about plasmolysis is held to indicate the penetration 
of the solute into the cells in these cases, while the occurrence of 
plasmolysis with the mixed solution indicates the non-entrance of 
the solutes from the mixed solution. As the osmotic concentration 
of the mixed solution is so little different from (actually a little less 
than) that of the pure sodium chloride solution, and as the con¬ 
centration of sodium chloride is reduced by only about 9 per cent., 
it seems improbable that the smaller rate of entrance of the salt on 
account of the lower concentration of sodium chloride would alone 
be sufficient to account for plasmolysis taking place in the mixed 
solution, and it seems most likely that the capacity for the molecules 
of sodium chloride to enter the cell is reduced. 
The influence of one salt on the intake of another by young roots 
of yellow lupin has been investigated by Kahho (1921 d) by the tissue 
extension method. It will be recalled that Kahho found kations 
absorbed in the order K, Na, Li, Mg, [Ba, Ca], while anions fall into 
the series [Br, I, N 0 3 ], Cl, tartrate, S 0 4 , citrate. When the entrance 
of single salts and that of mixtures of two salts are compared, the 
solutions in all cases being isotonic, it is found that the entrance 
of any kation in the series is retarded by the presence of any other 
kation to the right of it in the series, the further the kation lies to 
the right the greater the retarding effect. Thus, potassium chloride 
enters much more rapidly than lithium chloride presented in the 
