398 THE DIPHTHERIA BACILLUS GROUP 



neutralize all except sufficient toxin to kill a 250 gram guinea-pig 

 in four days contains 100 antitoxin units in the example cited. 

 Knowing the dilution of the antitoxin, it is a simple problem to deter- 

 mine the number of units in 1 c.c. A good antitoxic serum should 

 contain from 200 to 700 units per cubic centimeter of the unconcen- 

 trated product. 



Curative Value of Diphtheria Antitoxin. Diphtheria antitoxin 

 should be used as early as possible in order to obtain the maximum 

 curative effect. This is clearly set forth in the following table. 1 



Day of Cures. 



Totals 233 179 54 77 



According to Donitz and others, the initial dose of antitoxin should 

 be large; it is believed that with large doses of antitoxin even some 

 of the toxin attached to the tissue cells can be neutralized. For this 

 purpose 4000 units is a minimal initial dose, and severe or desperate 

 cases are given 10,000 to 100,000 units. The antitoxin should be 

 repeated the following day if necessary. It is better to administer 

 too much than too little antitoxin. Antitoxin given subcutaneously 

 is least dangerous so far as danger from anaphylaxis is concerned 

 but the absorption is slow. Intramuscular injections, particularly 

 in the gluteal region, are said to be more efficient curatively. In des- 

 perate cases intravenous injections of antitoxin (without carbolic 

 acid as a preservative if possible) are indicated. 



Active Immunization with Toxin- Antitoxin Mixtures. Following a 

 suggestion of Theobald Smith, 2 Von Behring 3 has attempted to create 

 active immunity to diphtheria in man by subcutaneous injections of 

 toxin-antitoxin mixtures which are neutral or but slightly toxic for 

 guinea-pigs. The few observations which are available are on the 

 whole encouraging, but do not justify a formal opinion of the practical 

 value of this procedure. 



1 Quoted from Citron, Immunity. 



2 Jour. Med. Research, 1907, xvi, 359. 



3 Deutsch. med. Wchnschr., 1913, p. 873. 



