290 



DAVID R. BRIGQS 



many of the improvements that had appeared in earUer apparatus. 

 His original apparatus has been further improved by Longsworth and 

 Maclnnes {26). Modifications in the manner of detecting and re- 

 cording the refractive index changes that occur through the boundary 

 have been made by Longsworth (27), Svensson {29), Philpot {28), and 

 others. A description of the Longsworth-Maclnnes modification of 

 the Tisehus apparatus will serve to illustrate how and to what extent 

 the requirements enumerated above have been met in modern moving- 

 boundary electrophoresis apparatus. A detailed description of the 

 installation and use of this instrument has been given by Longsworth 

 {30). 



3 



Fig. 3. Moving-boundary electrophoresis cell 

 of Tiselius with supporting frame, electrodes, and 

 electrode vessels, showing mechanical devices for 

 moving segments of the cell as required during fill- 

 ing of cell and formation of boundaries. 



Fig. 4. Analytical cell 

 showing sectional con- 

 struction that makes 

 possible formation of 

 sharp boundaries. 



In Figure 3 is shown, diagrammatically, the construction of a 

 modified Tiselius U-tube apparatus (with supporting frame) and 

 Figure 4 is a drawing of the cell proper, i.e., the U tube in which the 

 boundaries are formed and allowed to migrate electrophoretically. As 

 illustrated in Figure 3, this cell (TF) is connected through rubber 



