208 BOTANICAL GAZETTE [SEPTEMBER 
by means of a hand press giving about 300 kgm. per sq. cm., the 
tissue having been coarsely cut up with scissors and wrapped in a 
single layer of art canvas. The freezing point was determined with 
the BECKMAN apparatus, following the directions given by HAm- 
BURGER (10). Both osmotic pressure and permeability were 
investigated by the plasmolytic method. Plasmolysis was ob- 
served in the cortical cells just underlying the epidermis at the 
base- of the second leaf scale (that is, second from cotyledons). 
Plasmolytic agents employed were sucrose, glucose, KNO;, an 
glycerine. A solution was considered isotonic with the cell sap 
if it just caused plasmolysis after 30 minutes. The temperature 
was 20-24 C. 
‘TABLE VIII 
OSMOTIC PRESSURE BY FREEZING POINT 
No. of sample A bata Mean pressure 
Vv 0.610 re es Beer 
Untreated: 2.2. -. VII 0.632 605 oh eee 
XI 0.703 Sih 82 Wie eee 
Wieseias AU five b Ee RRA See es 799 
IV 0.755 0.05 fees eee 
0.818 0:84 eas ieee 
Ethylene treated ag Vill °. 827 TE? ERE SOMERS 2G ta gi de 
0.782 O40 OA re 
XIV 0.821 9 .8e ee 
Me Pomecriuccs tis meh oy ries 9.63 
In table VIII are the results by the freezing point method. It 
is evident that the juice of the treated tissue has a higher osmotic 
pressure than that of the control, a difference of about two 
atmospheres. 
Similarly, table IX gives the results by the plasmolytic method. 
The figures show that the same relative difference of about two 
atmospheres exists between the treated and untreated tissues, 
although the pressures themselves are somewhat higher. RICHTER 
(31) and others have assumed a rise of osmotic pressure in tissues 
under the influence of anaesthetics. This assumption is based 
upon the fact that sugars and other osmotically active substances 
were known to increase. However, no previous measurements 
