IMMUNITY 77 



Serum Treatment. Since it is possible to create 

 in animals by the injection of bacteria, a condition of 

 the blood serum which neutralizes the bacterial poisons, 

 there has arisen a specific treatment of many bacterial 

 diseases. The ones found most suitable for this therapy 

 are diphtheria, tetanus, meningitis, dysentery, cholera, 

 streptococcus, and pneumonia. The antiserums are 

 administered by injection under the skin of patients, 

 and serve the purposes first of neutralizing any poison 

 which may be circulating, of agglutinating free germs, 

 of stimulating the phagocytes to devour the organisms, 

 and of keeping the poisons from destroying the cells 

 of the organs. The various antisera will be discussed 

 under their respective diseases. 



Anaphylaxis. When the principal constituent of 

 flesh and blood, protein, is taken into the alimentary 

 tract it is digested and absorbed because digestive 

 ferments are there for the purpose. If it be injected 

 in solution under the skin a ferment has to be prepared 

 in order to remove it. If, now, it be injected a second 

 time this ferment is ready and attacks the protein, 

 digesting it rapidly. The products of this digestion 

 appearing suddenly in the tissues are apt to poison 

 them. If a guinea-pig be injected with horse serum 

 and the dose be repeated ten days -later, the animal 

 will have dyspnea, skin irritability, and die. This is 

 anaphylaxis, which we shall for our purpose con- 

 sider as a hypersusceptibility to protein matter not 

 taken in the normal manner. Some persons exhibit 

 great susceptibility to antiserum injection because 

 they are anaphylactic to the horse serum, and while 

 a few deaths have occurred, they usually react by the 



