OPIUM 129 



small, and as a consequence there has been no 

 evolution against it. Races which have longest 

 used tobacco are as ardent (but not more ardent) 

 votaries of nicotine as races newly introduced to it. 

 In all this tobacco furnishes a close parallel to 

 chicken-pox. 



Immunity can be acquired against measles ; but 

 not so easily as against chicken-pox. Measles is 

 therefore the cause of a considerable death-rate, 

 and consequently of evolution. But the death-rate 

 is not so large as that occasioned by consumption, 

 nor is the consequent evolution so tedious and 

 difficult, and therefore so great. Opium furnishes 

 the parallel. It is very poisonous to the beginner — 

 more poisonous than alcohol, just as measles is at 

 first more poisonous than consumption. But the 

 immediately poisonous effects diminish till doses a 

 thousandfold greater than those which were at first 

 poisonous can be tolerated. The opium smoker or 

 drinker becomes more and more immune. But 

 there is a limit to safe indulgence. Unlike the 

 tobacco smoker the enjoyment of the opium 

 inebriate is not always contained within harmless 

 bounds. If he craves greatly for deep indulgence, 

 and as a consequence indulges very greatly, he 

 becomes, like the alcohol inebriate, constitutionally 

 poisoned. Opium is therefore the cause of a con- 

 siderable death-rate, and therefore, as we shall see, 



I 



