SERUM THERAPY 97 



the wound in hopes of rendering inert any toxin which 

 has not yet entered the circulatory system. 



Antimeningitis Serum. This serum, like others, is 

 prepared from the horse. In the beginning, alternate 

 injections of dead cultures of diplococcus meningitidis 

 and cultures which have undergone autolysis are injected. 

 Autolysis is a process of self-destruction of the germs 

 which takes place as follows: 10 to 20 c.c. of normal 

 salt solution is poured over a twenty-four-hour culture 

 of the germ. The cultures are separated from the 

 medium by agitation and the flask placed in an incubator 

 for twenty-four hours, when the fluid resulting will be 

 found free from diplococci and to contain only granular 

 debris and solution of diplococci. After several weeks 

 the dead culture, which is alternated with the autolysate, 

 is replaced by living cultures. The injections are con- 

 tinued in increasing doses over a period of four to six 

 months, when the serum of the animal is tested. When 

 it is found active in a dilution of i : 5000 it is considered 

 fit for use, and the horse is bled and the serum preserved 

 as are other serums. 



Action of the Serum. The mode of action of antimen- 

 ingitis serum is probably more complicated than that 

 of antidiphtheric serum. It seems to combine the 

 action of a bacterial vaccine with that of an antitoxin. 

 By its opsonic action it increases phagocytosis. The 

 phagocytic destruction of the diplococci sets free their 

 toxin, which the antibodies of the serum are then able 

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