470 



BOTANICAL GAZETTE 



[JUNE 



increase in permeability might escape notice. With more delicate 

 methods an increase under these conditions might appear. In 

 heating the peanut seed coat a brownish extract was obtained, and 

 it is thought that the increase was due in a large measure to the 

 removal of the soluble substances. The nature of these sub- 

 stances will be treated in that portion of the paper dealing with 

 microchemical and chemical tests. 



TABLE I 



Effect of extracting membranes with boiling water 



Membrane 



Peanut . . . 



a 

 u 



u 



a 

 u 

 a 



a 



Almond. . 

 Grapefruit 



a 



Squash . . . 



u 



Area in sq. 

 mm. 



I9-635 



.. 



a 



50 

 19 

 5° 



265 



635 

 265 



U 



19-635 



u 

 a 

 a 



Concen- 

 tration of 

 solution 



0.5 M 



a 



O 

 O 

 O 

 O 



6M 



5M 



6M 

 5M 



u 



0.5 M 



Saturated 



a 



Rate before 

 extraction 



28.31 



32.35 

 35.05 



89-54 



54-67 

 34-67 



88.56 



40.44 



I7-52 



o 

 o 

 o 



Rate after 

 extraction 



66 

 82 



US 

 212 



150 

 114 



210 



101 



105 

 o 



o 



o 



II 



73 

 90 



59 



3 1 



00 



30 

 00 



10 

 14 



76 





Percentage of 

 increase 



135.7 



156.3 

 229.8 



137.2 



174-4 



229.7 



I37-I 



150.O 



500.I 



Membrane 



Peanut 



TABLE II 

 Effect of heating dry membranes 



Area in sq. 

 mm. 



19-635 

 50.265 



Concen- 

 tration of 

 solution 



Rate before 

 heating 







0.5 M 



0.8 M 



28.31 

 78.86 



Rate after 

 heating 



42.47 



101. 10 



Percentage of 

 increase 



50 -03 

 28.2 



To gain further information on this point, the effect of heating 

 the dry membrane was compared with the effect of heating the 

 membrane in water. The permeability of a membrane was first 

 measured; it was air dried, placed in a glass tube, and the latter 

 heated in water as described. The membrane was then soaked 

 in water, placed in the osmometer, and a reading again made of its 

 permeability. Table II expresses these results. 



