108 VACCINE AND SERUM THERAPY. 



having a medium incubation period die, while of the cases with a 

 long incubation period, 52.9 per cent of the patients die. 



Tetanus anti -toxin can only bind tetanus toxin before it is 

 taken up by the nerve cells and axis cylinder. Frequently, how- 

 ever, the disease is not suspected until after the symptoms appear. 

 Because of this the value of tetanus anti-toxin lies mainly in its pro- 

 phylactic application. As a preventative of tetanus, tetanus anti- 

 toxin has proven to be of great value. However to obtain bene- 

 ficial results injections should be made early, as soon after in- 

 fection as is possible, and inasmuch as immunity lasts only two 

 to three weeks, the injections should be repeated as long as danger 

 of infection exists. The immunizing dose which is generally 

 used^ consists of fifteen hundred immunity units. The wounds 

 after which immunizing doses of tetanus anti-toxin are to be 

 used are those made by burns with toy pistols, fire-works, pistol 

 shot wounds, injuries occuring while working about the stable 

 or infected with fertilized garden earth or manure. The value of 

 this method cannot be definitely determined, for if tetanus anti- 

 toxin is used successfully, it is difficult to decide whether or not 

 there has been infection with the tetanus bacillus. It is the be- 

 lief of some, however, that tetanus can be prevented entirely if 

 after all injuries of the kind likely to be infected with tetanus 

 bacilli immunizing doses of tetanus anti-toxin are injected early. 

 Jordan states that in the United States in 1903, there were 4,449 

 Fourth of July injuries, of which 406 cases died of tetanus ; while 

 in 1907, when tetanus anti-toxin was used quite universally for 

 such wounds, there were only sixty-two deaths caused by tetanus, 

 following 4,413 Fourth of July injuries. 



The use of tetanus anti -toxin as a curative measure has not 

 given universal success. This is undoubtedly due to the fact 

 that after the symptoms appear the tetanus toxin has already 

 combined with and injured the nerve cells, and is no longer amen- 

 able to neutralization with tetanus anti -toxin. It is usually 

 conceded that if tetanus anti-toxin is not given within thirty hours 

 after the appearance of 'symptoms, subcutaneous injections of 

 anti-toxins is of little avail. When the disease has advanced, 

 the large nerves in the vicinity of the infection and the spinal 

 canal have been injected. The therapeutic dose of tetanus anti- 

 toxin administered varies. If it is a case of short incubation, that 



