70 RELATION OF BACTERIA TO DISEASE 



beneath the skin of the individuals whom it is desired to 

 protect, beginning in minute doses and increasing the 

 quantity as the condition permits. By this means the resist- 

 ance of the animal or person to this particular germ is 

 increased, and the process corresponds to that of the produc- 

 tion of antitoxin in horses, that is, making an antipoison, or, 

 as it is called, an antibody. The method just described is 

 usually reserved for the bacteria which produce intracellular 

 or endotoxins. The method has been used in treating anthrax, 

 typhoid, cholera, etc. 



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 pneu- 

 monia. The antiserums are administered by injection under 

 the skin of patients and serve the purposes first of neutrali- 

 zing 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 fer- 

 ment 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 consider as a hypersusceptibility to protein 

 matter not taken in the normal manner. Some persons 



