BACTERIOLOGICAL TOXINS AND ANTITOXINS 121 



united with the nerve cells it is difficult or impossible to effect its 

 neutralization ; hence the greatest value of tetanus antitoxin lies 

 in its administration as a prophylactic. As a prophylactic remedy 

 it is even of more value than diphtheria antitoxin ; therapeutically, 

 it is less beneficial, since the tetanus toxin combines so rapidly and 

 firmly with the nerve cells. Recently, however, a method has 

 been employed which has met with considerable success. A mod- 

 erate amount of spinal fluid is removed by a spinal puncture 

 and from 3000 to 5000 units of tetanus antitoxin in a volume of 

 from 3 to 10 c.c. of normal salt solution is injected slowly by 

 gravity; at the same time 10,000 units are given intravenously 

 or intramuscularly. 1 As a prophylactic measure from 1000 to 

 1500 units are injected intramuscularly. 



It is generally agreed that since tetanus is almost invariably 

 associated with a wound, proper treatment of the original lesion 

 combined with the immediate administration of antitoxin will 

 surely prevent its development. 



Production of Tetanus Antitoxin. As in the case of diphtheria 

 a strong toxin is first prepared. Suitable broth is inoculated with 

 tetanus bacilli and the organisms are grown anaerobically for two 

 weeks at 37 C. At the end of this period the toxin broth is 

 separated from the bacilli by filtration and its strength is deter- 

 mined by the same method as that employed for diphtheria toxin, 

 except in this case heavier guinea pigs are used. Those weighing 

 about 350 grams are chosen. The immunization of horses and 

 procuring of serum are also conducted in much the same way as 

 for the production of diphtheria antitoxin. 



For the standardization of the new antitoxin a standard toxin 

 with which to test it is obtained from the Hygiene Laboratory at 

 Washington. The unit employed is not quite the same as that 

 adopted for diphtheria. A unit of diphtheria antitoxin is defined 

 as the amount of antitoxin that will just neutralize 100 minimum 

 fatal doses of toxin for a 250 gram guinea pig. A unit of tetanus 

 antitoxin is defined as the amount of antitoxin that will just neutralize 

 1000 fatal doses of toxin for a 350 gram guinea pig. 



1 Park and Nichol, Jour, of the A. M. A., Vol 63, July, 1917, p. 325. 



