1917] 



DENNY— PERM EA BILITY 



471 



The results indicated in table II show that part of the increase 

 in permeability after heating in water is due to the heating effect 

 itself, and that not all the increase is due to the extraction of 

 materials from the membrane. 



Effect of extracting membranes with hot lipoid solvents 



The role of lipoid substances present in the membrane in limiting 

 the rate of penetration of water was investigated by determining 

 the permeability of a membrane before and after extraction of the 

 membrane with a lipoid solvent. The solvents used were alcohol, 

 acetone, and ether. After 4 hours' treatment with the solvent, the 

 solvent was removed from the membrane and the latter soaked in 

 water before being placed in the osmometer. Table III shows the 

 results obtained. In this series all membranes were previously 

 heated in boiling water. It will be noted that extracting the 



Effect of extr. 



TABLE III 



NG MEMBRANES WITH HOT LIPOID SOLVENTS 



Membrane 



Peanut 



a 



u 



u 



Squash 



u 

 a 



Almond 



u 



Cocklebur, 



a 



a 



Grapefruit 



• * 



Area in 

 sq. mm. 



50-265 



!9-635 

 50.265 



u 



« 



19-635 



50. 265 



a 

 u 



50- 265 



u 



19 635 



u 

 u 

 u 

 u 



a 



Concen- 

 tration of 

 solution 



Rate 

 before 

 extrac- 

 tion 



0.5 M 



0.6 M 



0.5 M 



u 

 a 



Saturated 



a 

 u 



a 

 a 

 a 



a 

 a 

 u 

 a 



92.67 

 5223 

 98.40 

 78.86 



151-65 

 101. 10 



113.24 



11. 12 



15 51 



11-45 

 60.66 



50-55 

 20. 22 



14-83 

 22.24 



o 



o 



o 



Rate 

 after ex- Percent- 

 traction age of 

 with hot increase 

 alcohol 



Rate 



after ex- 





Rate 

 Percent- after ex- 



Percent- 



14445 



9234 

 228.48; 



161 .76' 



257.80 



117.26 



242 . 65 



99.42 



82.90 



III. 22 



232.55 

 279.71 



48.28 



45.83 

 56.62 



O 



IO. II 



o 



55-9 

 76.8 



132.2 



112. 6 



69.9 



15-9 



114 3 



793 9 



434 5 



871.3 

 283.4 



452.3 

 138.8 



209.1 



154.6 



traction age of traction age of 

 with hot increase with hot increase 

 acetone I I ether 



171.87 



217.70 



IOI.IO 



98.07 



119.08 



234.89 



279.06 



40.44 



126.3 



169.84 



92.47 



92.2 

 809.2 



532 6 

 939 8 

 287.2 

 452.o 

 200.0 



279.06 

 I3I-43 



833 

 77.0 



84.1 

 SO.o 



membrane with lipoid solvents greatly increased the permeab 



to water, 

 ment fail 



case of the grapefruit seed did such treat- 

 increase. The different solvents did not 



