3 8o 



BOTANICAL GAZETTE 



[may 



pressure of the bathing solution due to changes in temperature. 

 The actual osmotic pressure of the solution at the temperature used 

 was calculated on the basis of proportionality between osmotic 

 pressure and absolute temperature. The observed rate was 

 corrected on the basis that the rate was proportional to the pull 

 applied, which will be shown later to be the case for solutions of 

 sodium chloride. When cane sugar was used as the bathing 

 solution the observed rate was not corrected, because proportion- 

 ality between rate and pull applied does not exist with such 

 solutions. 



TABLE III 



Value of Q 



10 



5 .2-i5?2C 



i5-2-25°2C. 



25-2-35°oC 



35 • 0-45°° C. 



1.688 



1.564 



1-374 



1-332 



i. 



1 



661 



I . 



528 



1 339 



« i-39° 



i. 



716 



I. 



512 



1.258 



1-259 



i. 



609 



I. 



546 



1. 206 



1.364 



i 



637 



I 



487 



1-433 



i-3<>5 



i 



53o 



I 



507 



1.448 



1 .411 



i 



579 



I 



610 



1.388 



1.204 



1.608 



I 



449 



1. 298 



1.384 



Average, 1.628 



1525 



1-343 



- 1.344 



TABLE IV 



Effect of temperature upon permeability of seed coat (membranes 



of Arachis hypogaea) 



Number 



I 



2 



3 



4 



5 



Osmotic pressure 



of cane sugar 



solution at 



25 



°C. 



21.25 



u 



u 

 u 



Water (inmg.) passing through 19.635 sq. mm. of membrane per hour 



3?6C 



7-98 



13 12 

 II .64 



6-39 

 14-55 



I3?6C 



13 



21 



19 

 IO 



23 



69 

 II 

 40 



27 



39 



2 3 ?6C 



20.54 

 30.07 



28.92 

 I4-38 



35 09 



33?6C 



26.81 

 42.21 



38.79 



19 5 1 



46.89 



may estimate the coefficient 



in 



Q I0 . Experi- 



which 



bathing medium instead of sodium chloride. The results with 

 cane sugar are given in table IV. The figures in table IV give 



