ANTITETANIC SERUM 133 



serum. Such a serum is stated to contain from 20 to 40 

 normal units of Behring per c.c. 



Antitetanic Serum. — The antitoxic treatment of tetanus 

 has received a great deal of attention, and much experi- 

 mental work has been done upon the question by Behring 

 and Kitasato in Germany, and by Tizzoni and Cattani in 

 Italy. The former investigators found that immunity 

 could be conferred upon an animal by the injection of 

 small but increasing doses of the toxins, but the degree of 

 immunity so conferred was not very great. More successful 

 results were obtained by injections of toxin mixed with 

 small amounts of iodine terchloride. 



Tizzoni and Cattani conferred immunity by injections of 

 broth cultures of the living organisms, which had been 

 attenuated by heat and other methods. Both these 

 methods were very successful in immunising susceptible 

 animals not only against very large amounts of tetanus 

 toxin, but also against injections of the virulent bacilli. 

 The immunity so conferred lasts for several months at least, 

 and the serum of these protected animals also confers 

 immunity on other animals. 



Roux and Vaillard immunise horses as follows, the treat- 

 ment lasting about three months: The virulent tetanus 

 bacilli are cultivated in a broth culture, in an atmosphere 

 of hydrogen, in specially constructed flasks. After about 

 fourteen days' growth, the culture is filtered through a 

 porcelain filter to free it from bacUU. Injections are then 

 made with this toxin daily, subcutaneously or intravenously, 

 starting with 1 c.c. of iodised toxin, gradually increasing 

 the dose until the pure toxin can be injected without 

 danger. The serum is standardised from time to time, and 

 the blood is drawn off and the serum prepared by the 

 methods aheady described in the case of antidiphtheric 

 serum. It must be admitted that the clinical results 



