Studies of Protoplasmic Permeability by Measurement 
of Rate of Shrinkage of Turgid Tissues. 
I. The Influence of Temperature on the Permeability 
of Protoplasm to Water. 
E. MARION DELE, 
Yarrow Fellow , Girton College , Cambridge. 
With seventeen Figures and five Tables in the Text. 
Table of Contents. 
PAGE 
Section I. Introduction . . . 283 
,, II. Apparatus and Regula- 
tion of Temperature . 284 
,, III. Procedure in a Typical 
Experiment . . . 286 
„ IV. Characteristics of the 
Material used . . 2S9 
A Onion Leaves . .289 
B. Dandelion Scapes . 292 
,, V. Choice of a Solution for 
investigating Rate of 
Plasmolytic Shrinkage 
page 
Section VI. Rate of Plasmolytic 
Shrinkage in a Subtonic 
Solution .... 295 
A. Leaf of Onion . . 295 
B. Scape of Dandelion 300 
VII. Critical Consideration 
of the Relation between 
Permeability and Tem- 
perature put forward 
BY F. VAN RYSSELBERGHE 305 
VIII. Summary and Conclu- 
sions .... 308 
55 
293 
Introduction. 
T HE effect of temperature on the permeability of protoplasm to water 
has much interest biologically, but no critical work dealing with it 
has hitherto been published. It was known that, generally speaking, 
root absorption is retarded by low soil temperatures, and Wieler states 
that the bleeding of vine stems is accelerated eight times by a rise in 
temperature from 8° to 42 0 C. The first attempt to measure the tempera- 
ture effect was the work of Krabbe in 1895, and was based on the 
plasmolysis of cylinders of turgescent pith tissues at different tempera- 
tures, the time required for the total contraction in any given solution 
varying with the temperature. This method was adopted by van RysseE 
berghe in 1901, and extended to the consideration of the passage of water 
through the protoplast both in plasmolysis and deplasmolysis. According 
[Annals of Botany, Vol. XXX. No. CXVIII. April, 1916.] 
