ma 
30 BOTANICAL GAZETTE [JANUARY 
in water, and on complete plasmolysis a still larger proportion — 
showed the cortex longer than the axial cylinder. This differ- 
ence in length was often greater in the same root after plasmol- 
ysis than before. The observations were made with the unaided 
eye or with a lens of about ten diameters. Even though there 
was a small number of roots in which the cortex was under nega- 
tive tension, it is clear from the table that in the large majority 
of cases the cortex is under positive tension and the axial cylinder — 
under negative tension. 
wil a Tha aa 
A series of experiments designed to ascertain the effect of _ 
stimulation on tissue tensions, as indicated by difference in 
length of separated tissues, is shown in table VII. 
TABLE VII. 
EFFECTS OF STIMULATION ON TENSION. 
3 e : bd s < : g : 3 
o = Ss : 
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Date 1897 2 55 ae a. oe or | BEA Se 
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January 16 - - I I i 
April 20 - . 22 6 2 5 8 I 
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ities a | BNC etary 
In these experiments the roots were branded and as soon as 
y began to curve, or while the c 
such a way that the three 
axis, and convex cortex lay in the plane 
