Studies in Permeability. 
V. The Swelling of Plant Tissue in Water and its Relation 
to Temperature and various Dissolved Substances . 1 
BY 
WALTER STILES 
AND 
INGVAR J0RGENSEN. 
With ten Tables and nine Figures in the Text. 
Contents. 
PAGE 
Introduction 415 
Method of Experiment .416 
The Variability of the Tissue used and the Probable Error of Experiment . 417 
Experimental Results : 
(<z) The Swelling of Potato and Carrot in Water 4T9 
(< h ) The Influence of Temperature on the Swelling of Potato and Carrot 
in Water 421 
( c ) The Influence of Dissolved Substances on the Swelling of Potato . 424 
Concluding Remarks 430 
Summary 433 
Literature cited 434 
Introduction. 
T HE passage of substances between plants and their surroundings, and 
between cell and cell, is a subject of fundamental importance. Thus 
among the problems to which such phenomena have application may be 
mentioned those of carbon assimilation, translocation, transpiration, and 
root absorption, with their bearing on agriculture ; the extraction of sub- 
stances from living or dead plant tissue ; and even such problems as those 
involved in the preservation of vegetables and fruits. Nevertheless, in spite 
of the wide importance of the subject, the known facts are few and often 
not very definite, so that the information so far available does not enable 
us to attempt an analysis of the processes involved. For although the 
single term ‘ permeability ’ is used in relation to these phenomena, it is to be 
expected that the processes are numerous and not all of the same nature. 
Obviously a detailed analysis of the processes of permeability is 
1 The terms swelling and shrinkage are used in a general sense and refer to the total gain or loss 
of water by the cell under various conditions. Pfeffer used the term swelling in a restricted sense to 
indicate the water imbibed by the protoplasm, as distinct from that absorbed by osmosis. 
[Annals of Botany, Vol. XXXI. Nos. CXXIII and CXXIV. July and October, 1917. J 
