Chapter III 



DEVELOPMENT OF IMMUNE THERAPY 



The fact that individuals who recover from 

 certain infectious diseases are immune has been 

 known since the earliest times, and was noted by 

 Thucydides in relation to the plague at Athens. 

 In China, practical application of the observa- 

 tion was made as early as 1000 A.D. by exposing 

 children to smallpox or actually inoculating 

 them with dried lymph, in order to produce a 

 mild form of the disease which they usually 

 survived and which rendered them immune. 

 Among certain castes in India and some of the 

 wild tribes of Africa it was the practice to im- 

 munize individuals with small doses of snake 

 venom as a protection against subsequent bites. 

 Smallpox inoculation was introduced from Asia 

 among Western nations in the eighteenth cen- 

 tury. Inoculations of cowpox as a protection 

 against smallpox had also been practised in 

 England and on the Continent in isolated in- 

 stances; but it was not until Jenner had made 

 his observations that the value of the method 



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