530 



EDMUND NEWTON HARVEY 



3. Experwients with plant cells 



a. Strongly dissociated alkalies: The leaf of Elodea, except at 

 the midrib, is only two cells thick, a layer of small cells con- 

 stituting the lower surface, a layer of much larger cells above. 

 There is great variation in different leaves in the time for the color 

 change to take place, as well as individual differences among the 

 separate cells. A consequence of the latter fact is the decoloriza- 

 tion (in K, Na, or N(C2H5)40H ) of the leaf in patches, groups 

 of red cells becoming yellow before others. The phenomenon 

 is not marked in Ca, Sr, and Ba. Spirogyra exhibits the same 

 variability as Elodea. 



A comparison between the inorganic hydroxides was made 

 with TO alkali in tightly corked bottles, to prevent absorption of 

 CO2. The water was redistilled from glass and was non-toxic to 

 Spirogyra, Elodea and Paramoecium. Paramoecium is especially 

 sensitive to commercial distilled water and may be used as an 

 indicator of the purity of a water. Elodea showed rotation in 

 commercial distilled water after 24 hours. Nevertheless the rate 

 of entrance of NaOH is more rapid when dissolved in commercial 

 distilled water than in pure redistilled water and more rapid in 

 pure redistilled water than in tap water. 



The following table constructed from many experiments gives 

 the relative rate of penetration of N(C2H5)40H, Na, K, Ca, Sr, 

 and Ba hydroxides^ The actual times varied somewhaf in indi- 

 vidual experiments, but the relation order of penetration was 



Penetration of 5^5 alkali into Elodea leaves. 



MINUTES 



NaOH 25 



KOH 22 



Ca(OH)2 23 



Sr(OH)2 15 



Ba(0H)2 15 



MINUTES 



N(C2H5)40H 30 



NH4OH 0.5 



Methyl amine 1 



Trimethyl amine 2 



* 1 am indebted to the Chemistry Department of Columbia University for 

 methyl, dimethyl, trimethyl, ethyl, propyl, and isopropyl amines. Tetraethyl- 

 ammonium hydroxide was obtained from Merck and Co. The inorganic hydrox- 

 ides were Eimer and Amend's C. P. with the exception of Ba(0H)2, which 

 was manufactured by Kahlbaum. 



