ANTITOXINS AND RELATED ANTIBODIES 



143 



tralized by the addition of sodium carbonate, and dialysis is con- 

 tinued until the soluble salts have practically disappeared. If 

 care is used, the antitoxin will be found to be dissolved in a much 

 smaller quantity of water than originally present in the serum. 

 The concentration may be from two to three and one-half times 

 the original. 



Banzhaf makes use of the various coagulation temperatures 

 of the serum constituents in effecting their separation. The 

 albumins and part of the non-antitoxic globulins are precipitated 

 by heating for twenty-four hours at 58. Sodium chlorid crystals 

 are added to saturation, and much of the remaining globulin, 

 transformed by heat, is precipitated, leaving the pseudoglobulins 



Fig. 71. One type of nitration apparatus used for serum: a, Filter; 6, 

 test-tube within a filter flask from which the air is partially exhausted by 

 the vacuum pump at d (Weidanz). 



and the associated antitoxin in solution. The clear filtrate is 

 acidified with acetic acid, and the precipitate prepared as in the 

 preceding method. By this method a concentration of ten times 

 the original has been obtained. 



The antitoxic serum is in all cases filtered through sterile un- 

 glazed porcelain, and, after the addition of a small amount of 

 preservative, placed in sterile containers and sealed. 



Preparation of Tetanus Toxin and Antitoxin. The tetanus 

 toxin is prepared by growing Bacillus tetani in broth under anaerobic 

 conditions. This may be accomplished by the use of a hj'drogen 



