TECHNIQUE OF ELECTROCHEMICAL MEASUREMENTS 467 



most rapid in the period of time preceding the attainment of this 

 minimum, so that even the minimum potential may be consider- 

 ably in error, especially as in the chains containing these solutions 

 the potential was low and 1 mm. displacement on the bridge 

 introduced a considerable error into the determination of the 

 potential. This error is diminished in its percentage magnitude 

 in the calculation therefrom of m, the amount of alkali neutralized 

 by the protein, but, nevertheless, the determination of m in the 

 solutions mentioned is not to be considered trustworthy. In less 

 alkaline solutions no effect upon the hydroxyl-concentration of 

 the caseinate solutions, due to hydrolysis, could be discovered; 

 had such an effect been present to any appreciable extent it would, 

 of course, have been detected in these solutions much more readily 

 than in those in which such an effect was detected, since the poten- 

 tials of the chains containing these solutions were higher, so that 

 a smaller change in hydroxyl-concentration of the solution would 

 have produced a greater (absolute) displacement of the neutral 

 point upon the bridge-wire. 



In concluding these remarks, it may be stated that unless all of 

 the precautions which have been described are observed with the 

 utmost fidelity the results of experiments such as these, and con- 

 ducted in this manner, will be found to be wholly irregular, and, 

 save in a qualitative sense, untrustworthy. 



