148 



Scientific Proceedings (39). 



94 (504) 



The precipitation of diphtheria antitoxin hy means of 

 precipitins. 



By J. P. ATKINSON and E. J. BANZHAF. 



[From the Chemical and Research Laboratories of the New York 

 Department of Health.] 



This work was undertaken partly to check and to review the 

 previous observations by one of us a number of years ago on the 

 precipitation of diphtheria antitoxin from solutions by means of 

 antibodies prepared by injecting diphtheria antitoxic globulin and 

 globulin of normal horse serum into rabbits, 1 partly to determine 

 whether such a method could be used in the further purification 

 of diphtheria antitoxin. 



In these earlier experiments it was found that the antibody 

 formed by the injection of globulin of normal serum into rabbits 

 threw out of solution diphtheria antitoxin just as well as the anti- 

 body formed by the injection of diphtheria antitoxic globulin. 



We undertook these last experiments with the purest diphtheria 

 antitoxin fractionated from the globulin, and serum globulin frac- 

 tionated in the same way and under the same conditions. The 

 sera were kept at 56 0 C. for fifteen hours to convert, as far as 

 possible, pseudo-globulin into eu-globulin. The diphtheria anti- 

 toxin under these conditions remains unchanged with the pseudo- 

 globulin. 2 The solution was then half saturated with ammonium 

 sulphate and the precipitated globulin filtered off. The precipitate 

 was washed with saturated sodium chloride to remove the pseudo- 

 globulin. The sodium chloride solution was precipitated with 

 acetic acid and again filtered and squeezed between filter paper 

 to remove excess of salts, especially ammonium sulphate, and 

 finally dialyzed to free it as completely as possible from salts. 

 Putrefaction was prevented by the presence of chloroform. The 

 dialyzed globulin in the case of the diphtheria antitoxin was highly 

 concentrated and is the antitoxin of commerce today. 



Both sera, antitoxic and normal, were put through exactly the 

 same process in preparing the globulin for injection. 



■J. P. Atkinson, Med. News, 1904. Ixxxiv, 375. 



2 Banzhaf, Proc. of the Soc. for Exp. Biol, and Med., 1908, vi, 24. 



