CHAPTER XI 



OPIUM 



Parallel between diseases and narcotics — The evolution against 

 opium more easy than that against alcohol. The elimination 

 more thorough from the beginning — The evidence produced 

 before the Royal Commission on opium. 



Besides alcohol, many other narcotics are used by 

 different races. Chief among them are tobacco 

 and opium. A remarkable parallel obtains between 

 zymotic diseases and narcotics. We have seen 

 that immunity may be acquired against some 

 diseases, but that it cannot be acquired against 

 others. In the latter case — i.e. when immunity 

 cannot be acquired by the individual — if the disease 

 be death-dealing, a very long and tedious process 

 of selection results in the evolution of inborn 

 immunity. The race grows so resistant that the 

 majority of its members resist infection. Con- 

 sumption is an example. In the former case — i.e., 

 when immunity may be acquired by the individual 

 — the members of the race remain as susceptible 

 to infection as ever ; but there is evolved in them 



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