540 



EDMUND NEWTON HARVEY 



B. TO NaOH in distilled water — decolorized in 28 minutes. 



C. 0.075 m NaCl in distilled water — rotation unaffected 

 after 24 hours. 



Experiment 4- In this experiment the effect of salts, and the 

 penetration of NaOH into red stained Elodea and also Spirogyra 

 were studied. The salt solutions are all in distilled water. 



^y tap water NaOH 



|*n distilled water NaOH 



^0 NaOH + T^'o NaCl 



f^ NaOH + ^^ (100 NaCl + 1 CaCU) 



^0 NaOH + i^ (100 CaCl + 2.2 KCl) 



fo NaOH + y^o (100 NaCl + 2.2KC1 + 1.6 CaCU) 



mm. 



45 

 35 

 8 

 9 

 5 

 6 



Experiment 5. 



I'o tap water KOH 



:fo distilled water KOH 



^jj KOH + y glycerine in distilled water 

 ^fg KOH + ^ glycerine in distilled water 



jQ KOH + 1 urea in distilled water 



f^ KOH + J urea in distilled water 



Both the chloroform and alcohol in sufficient concentration 

 allow the more ready entrance of NaOH (experiments 1 and 2). 

 One-sixth saturated chloroform also retards plasmolysis by f 

 urea. Such a retardation must be due to the fact that urea can 

 enter chloroform cells more readily than normal cells. Urea 

 penetrates normal cells slowly. 



A most striking effect is exerted by the neutral salts on the 

 penetration of NaOH (experiments 3 and 4), especially with 

 Spirogyra. A concentration which may enter in distilled water 

 only after 10 minutes, passes the cell membrane instantly in tf 

 NaCl. The effect on Elodea is similar. Addition of CaCl2 

 prevents the ready permeability to NaOH*^. In Spirogyra the 



* No precipitate of CaCOa is formed. 



