298 Del/. — Studies of Protoplasmic Permeability by 
effects has not been made, but by using the first period of contraction 
immediately after the application of the sugar current, and by correcting 
for the concurrent temperature effect curves, of plasmolytic shrinkage from 
37 0 to 42 0 C. were obtained which were of similar form to those at lower 
temperatures, but correspondingly steeper. The method of correcting the 
curves is shown in Fig. 10, where the oblique line Y, Z is taken as the base 
line of the curve. This is, in effect, to subtract from the observed ccn- 
Fig. 11. Chart ot the course of the shrinkage-time curves of onion leaf at different tempera- 
tures. All the shrinkages were carried out in subtonic sugar solution (o’iS grm. M. cane-sugar). 
The individual curves are representative ones from a group taken at each temperature, and in all cases 
the absolute shrinkage is brought to a standard amount of 100 units as represented by the ordinates. 
traction at any point the temperature effect, estimated from the curve A 
previously obtained with distilled water only. 
It was not easy to repeat exactly the conditions of a high temperature 
experiment, but close temperature intervals of successive experiments were 
selected in order to make the results as representative as possible. 
After thus selecting a suitable curve for each of a number of tempera- 
tures, these were all plotted to the same scale, the contractions at any point 
being expressed as percentages of the total contraction in that experiment. 
These temperature curves for the onion are reproduced in Fig. 11, and the 
actual contractions observed are given in Table II. 
