190 CHEMISTRY OF THE IMMUNITY REACTIONS 



in alcohol but their nature is unknown; the antibody involved in the reaction is 

 referred to as the meiostagmin, but its relation to other antibodies is likewise 

 unknown. 



THE EPIPHANIN REACTION 



Besides reduction in surface tension, other physico-chemical changes result 

 from antigen-antibody reactions, including the rate of diffusion, the osmotic 

 pressure, and, in consequence, according to Weichardt, the neutral point to phenol- 

 phthalein of a mixture of barium hydroxide and sulphuric acid, is also changed 

 towards the acid side by antigen-antibody reactions taking place in the mixture.** 

 This phenomenon has been utilized by Weichardt, under the name of "epiphanin 

 reaction," to determine the occurrence of such interaction of antigen 'and antibody. 

 The reaction probably depends upon absorption phenomena, but the exact nature 

 of the change is not \et understood. According to Rosenthal,*^ the epiphanin 

 reaction is especiall}' suitable for demonstrating cancer antibodies and antigens, 

 but Burmeister*^ and others have not been successful with this procedure. 



8* See Weichardt, Berl. klin. Woch., 1911 (48), 1935; Rosenthal, Zeit. Im- 

 munitiit, 1912 (13), 383; Angerer and Stott^r, Mtinch med. Woch., 1912 (59), 

 2035. 



85 Zeit. Chemotherapie, 1912 (1), 156. 



8«Jour. Infec. Dis., 1913 (12). 459. 



