bacteriology in a nutshell. 



(l.) injections of attenuated 

 (weakened) virus. 



Injections of attenuated virus are given in 

 order to establish resistance against a suspected 

 infection. 



(ll.) injections OF KILLED ORGANISMS. 



This process is said to be the safest way to 

 vaccinate against typhoid fever, cholera and 

 plague. In the Pasteur Institute treatment of 

 hydrophobia, in the first treatment given, dried 

 spinal cord is the material used and it is believed 

 to contain killed virus. 



Principles of Serum Therapy Considered. 



For the sake of brevity and to simplify for 

 study, the principles of serum therapy may be 

 considered under three heads — namely : 



1 . Antitoxins. 



2. Bactericidal or Antibacterial Serums. 



3. Vaccination. 



We have already mentioned the chemical 

 union of toxin and antitoxin, which is believed 

 by many authorities to bring about neutral- 

 ization. 



Test Tube Mixed in a test tube at a given temperature 



Expenments. ^nd of a certain concentration, these authorities 



tell us that union takes place rapidly and com- 

 174 



