JACQUES LOEB 



487 



a stoichiometrical nature and that one Ba or Ca replaces two Na (or 

 two Li, K, or NHj. The maximum amount of salt formed is practi- 

 cally reached not far beyond pH = 8.0, which is so near the point of 

 neutraUty that practically no corrections for the values for titration 

 and only shght corrections for the values for conductivity are required. 

 Our conductivity curves are the corrected curves, i.e. from the meas- 

 ured values the conductivities of the pure alkali solutions of the same 

 pH are deducted. 



5.5' 

 5.0 

 4.5 

 4,0 

 3^ 

 3.0 

 2.5 

 2.0 

 1.5 

 1.0 

 0.5 



° pH4.8 5.1 5.4 5.7 6.0 6.3 6.5 6.9 7.2 7.5 78 8.1 8.4 8.7 9.0 

 • KOH 

 X Ba(0n)2 

 ANaOH 



Fig. 1. Ordinates represent amount of Na, K, and | Ba (expressed in cc. of 

 0.01 N Na) in combination with 25 cc. of 1 per cent gelatin solution, previously 

 treated with NaOH, KOH, or Ba(0H)2 respectively and freed from the excess of 

 salt by washing. Abscissae represent pH of the solution. Curves in all three 

 cases are identical, showing that one Ba replaces two Na or K. 



///. Action of Diferent Alkalies on the Conductivity and Osmotic 



Pressure of Gelatin. 



In order to obtain constant results we brought the powdered gela- 

 tin, as stated, to the isoelectric point by treating it for 30 minutes with 

 m/128 acetic acid at 20°C. The gelatin was then put on a filter, the 

 acid allowed to drain off, and then it was washed twice with 25 cc. of 

 distilled water at about 5°C. Then such gelatin, while on the filter, 

 was perfused three times with 25 cc. of a solution of NaOH or KOH, 



