I4 2 PHYSICAL CHEMISTRY IN MEDICINE. 



electrical behavior of dissolved protein in order to obtain 

 a better insight into its colloidal reactions will be apparent 

 to every one. I planned, therefore, to obtain, first of all, 

 native protein as free from electrolytes as possible in 

 order to have a stock material for testing the effect of 

 different conditions upon the electrical behavior of pro- 

 tein. From the standpoint of general technic, moreover, 

 it seemed of great value to use a material which through 

 extreme dialysis, or this in combination with repeated 

 freezing, had been rendered as free from salts as possible. 

 The electrical conductivity rendered possible through 

 the presence of ions is very great when compared with 

 that produced through the migration of colloids. In 

 order to render the latter apparent, very strong currents 

 must therefore be used, which in the presence of salts 

 lead to a great heating of the solution and also to a 

 masking of the phenomenon sought for through the 

 action of the products of electrolysis. In our experiments 

 we used, for example, a current of 250 volts and 6 amperes. 

 In this current ordinary blood serum burns, while our 

 salt-free serum allowed only a few millionths of the 

 current to pass through it. To test the migration of the 

 colloid in the electrical current we utilized an apparatus 

 similar to the one successfully used by BILLITZER in his 

 beautiful experiments. Three beakers of uniform size 

 were connected with each other by means of siphons. 

 The electrodes dipped into the two outer beakers, while 

 the middle one served as a control, the contents of which 

 should, of course, not vary. At the conclusion of the 

 experiment the nitrogen in all three of the vessels was 

 determined by KJELDAHL'S method. 



The results of a long series of electrical convection 



