Relation of Plasmolysis to Shrinkage of Plant Tissue. 43 
grams of discs were used prepared as described in an earlier paper', 
and the precautions there described for reducing the sampling error 
were taken. The percentage changes in weight observed in each of 
the three series are shown in Tables 1 to III. 
Table III. 
Swelling and Shrinkage of Red Beet in Sodium Chloride solution. 
Series 3 (Beet No. 3). 
0 33 N 
0-40 N 
0-45 N 
Percentage 
Percentage 
Percentage 
Time in hrs. 
gain 
Time in hrs. 
gain 
Time in hrs, 
gain 
in weight 
in weight 
in weight 
0-62 
32 
0-63 
-0-2 
0-67 
—4-1 
3-20 
7-0 
3-20 
—0-4 
3-25 
-4-2 
In the first series all the solutions employed were below the 
equilibrium concentration. In both the second and third the 
solution of sodium chloride in which neither gain nor loss in weight 
took place was approximately 0.4 N, and on the assumption that the 
hydrostatic pressure is small in comparison with the osmotic 
pressure we should say that a solution of 0.4 N is approximately 
isotonic with the cell sap. The changes in weight during the first 
five hours are shown graphically in Fig I. 
O 2. \ 6 
Time in hours 
Fig. 1. Change in weight of red beet root during immersion in distilled 
water and sodium chloride solutions of different concentrations. 
1 Ann. of Bot., 31, pp. 416-419, 1917. 
