20 ELECTRIC CHARGE ON NATURAL SOLUBLE 



beakers determined (e.g., by a nitrogen estimation by Kjeldahl's 

 method). 



In this way it was shown that serum albumin, after the removal 

 of electrolytes by dialysis for some weeks, tends to move but 

 slightly in an electric field. This fact was only obvious on pro- 

 longed electrophoresis. The addition of alkali or of alkaline 

 salts causes a marked wandering to the positive pole, while 

 added acid or acid salts promote a movement towards the nega- 

 tive pole. Neutral salts of the alkali or alkaline earth metals 

 do not have a noticeable effect on the direction of movement 

 of the protein. When, however, electrolysis has produced acid 

 at the anode and alkali at the cathode, these secondary products 

 cause the albumin to become charged, so that positive albumin 

 is produced in the acid, and negative albumin in the alkali. In 

 consequence the protein is repelled from the corresponding pole 

 and forced towards the centre. It is therefore necessary, in 

 using the above apparatus, to control this electrical repulsion 

 by determining the content of the central beaker. In the follow- 

 ing tables several examples of results are given. The albumin 

 content is measured by the volume of N/4 acid required to 

 neutralise the ammonia formed in a Kjeldahl determination. 

 (A = anode cell ; M = middle cell ; C = cathode cell.) 



Table i. 



Horse-serum dialysed for nearly Seven Weeks. 

 250 volts and 2 x io~ 5 amps. 



(At the end of the experiment there was no appreciable alteration 

 in reaction in the three vessels.) 



Time of Electrophoresis. 



