74 MODERN BIOLOGIC THERAPEUSIS 



other protein bodies are removed. Those pro- 

 teins which are eliminated do not contain anti- 

 toxin and are undesirable in the antitoxin solu- 

 tion. 



Later it was demonstrated by E. J. Banzhaf 

 that, if the proteins retained by the above pro- 

 cess were heated for several hours at 57 C., the 

 solubility of certain inert matter contained 

 therein was so changed that it was insoluble 

 in a saturated sodium chloride solution, while 

 the antitoxic protein remained soluble thus 

 permitting a further elimination of useless 

 material. 



By combining the above methods in connec- 

 tion with our own modification, our labora- 

 tories employ a method which is briefly as fol- 

 lows : The citrated plasma is diluted with 

 water, and sodium chloride is added up to li/o 

 per cent. This mixture is placed in a water bath 

 at a temperature of 57 to 60 C., and heated 

 for several hours. Heating the plasma causes a 

 certain non-antitoxic portion of the globulin 

 fraction to become insoluble in saturated sodium 

 chloride solution, which otherwise would dis- 

 solve and lower the potency of the refined 

 product. After heating, the antitoxin is mixed 



