202 



ELECTROCHEMISTRY 



the above picture of the chain of events is correct, be an even 

 multiple (1, 2, 4, 8, 16, etc.) of the quantity of alkali which is 

 just sufficient to form the first salt, i.e., to carry the casein into 

 solution. By interpolation from the above tables and by con- 

 tinuing the curves it is seen that for all of the percentages of casein 

 employed the constant maximal value of the combining capacity 

 for KOH is, as nearly as can be estimated, 180 X 10"^ equiva- 



180 

 lents per gram. Now -ttt ~ 1^-^ ^^> within the error of esti- 

 mation, 16. The experimental results are therefore in good 

 agreement with the theory and we may conclude that casein 

 forms the following salts with KOH : 



I containing 11 . 4 X 10"^ equivalents of KOH per gram of casein 

 II " 22.8 X 10-5 



III " 45.6X10-5 " " " " 



IV " 91.2 X 10-5 " " « « 

 V " 182.4X10-5 " " " " 



In forming the last of these salts 16 — N.HOC— groups (or a 

 multiple of this number) have been opened up. 



Similar experiments were carried out upon solutions of ovo- 

 mucoid in dilute acid and alkali; they are tabulated below: 



1 PER CENT OVOMUCOID IN KOH SOLUTIONS 

 (KCl in each solution = 0.01 N) 



1 PER CENT OVOMUCOID IN HCL SOLUTIONS 

 (KCl in each solution = 0.01 N) 



