G. MCGUIRE AND K. G. FALK 439 



3. Dialysis of gel from 1 (e) against distilled water. 



(a) Gel disappeared on continued dialysis (up to 6 days) against 

 renewed distilled water. 



(b) Increase in volume as in 2 (b) in every case. 



(c) Liquid became cloudy and lighter colored as in 2 (d) if the gel 

 disappeared. 



4. Dialysis of liquid from 2 (d) against tap water. 



(a) Cloudiness disappeared. 



(b) No further increase in volume. 



(c) Some flakes of gel separated. 



Toluene was present in all these experiments. However, long 

 continued shaking of the extracts with toluene produced no gel. 

 Bubbling air through the extracts also did not result in gel formation. 



Most of the experiments were carried out by dialyzing against 

 running tap water or distilled water. Some experiments dialyzing 

 against tap water or distilled water in large beakers gave the same 

 results. 



The difference in the behavior of the banana extract relative to 

 the gel formation upon dialysis against tap water and distilled water, 

 was evidently due to differences in the compositions of the two. The 

 pH of the tap water was found repeatedly to be 7.0 to 7.2 : that of the 

 distilled water about 5.0. An average analysis of the inorganic 

 constituents, as parts per million of the tap water was as follows :^ 



CaCOs 24 NaCl 5 



MgCOa 5 KNO3 1 



MgS04 10 SiOa 9 



The distilled water was practically salt-free. 



11. Dialysis of Banana Extract against Solutions of Definite Hydrogen 

 Ion Concentrations and Salt Contents. 



Banana extract was dialyzed for 48 hours at 10-1 5°C. in collodion 

 bags against the following solutions contained in large beakers with 

 the indicated results. Sodium hydroxide or hydrochloric acid were 



^ The analysis was obtained through the courtesy of Mr. Merritt H. Smith, 

 Chief Engineer of the Department of Water Supply, Gas and Electricity, New 

 York City. 



