SERUM THERAPY. 



(B) Curative Injections. 

 In active serum therapy (active immuniza- Antibodies 

 tion), injections of bacteria killed by heat are *P ^"^* • 

 given in small doses for the purpose of hasten- 

 ing the formation of the characteristic constit- 

 uents of the blood and other fluids of immune 

 animans known as "antibodies," or antidotes. 



(A) Prophylactic (Preventive) Injections. 



Active immunization consists of vaccination Vaccination, 

 and protective inoculations with the killed 

 organisms of typhoid fever, cholera and plague. 

 Depending upon the material injected, the 

 result gained is the formation of an antitoxin 

 or antimicrobic substance known as an ambo- 

 ceptor or "fixiator." 



(B) Inoculation With Virulent Organisms. 

 (i) Used principally in experimental work. 



Inoculations are given with a small amount of 

 the micro-organisms, that is to say, "a non- 

 fatal dose." 



(II) Inoculation with virulent organisms in- 

 to a tissue which has some material resistance. 

 In the early days of vaccination, virus taken 

 directly from those suffering with smallpox 

 was used. The success of the method is believed 

 to be due, in all probability, to unfavorable con- 

 ditions found in the skin which prevented the 

 development of virulence. 

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