310 THE EVOLUTION AGAINST NARCOTICS 



different men, thereby causing them to drink for diverse reasons, 

 it does not eliminate a particular type. The objection is merely 

 verbal. Whatever the shades of difference, all men drink because 

 the act awakens pleasurable sensations because it gives actual 

 pleasure or because it soothes discomfort or suffering. The type 

 which survives is one in which acute pleasure is not awakened nor 

 suffering soothed by deep indulgence. It would be as reasonable 

 to argue that carnivora are not causes of evolution in antelopes 

 because some of the latter are eliminated on account of dull hear- 

 ing, others for defective sight, others for insufficient speed, and so 

 forth. Nor, as we have seen, is the argument valid that selection 

 is not selection because it varies in intensity with time and place, 

 and is never absolutely thorough. Some people ask how the 

 susceptibility to the charm of narcotics can have arisen in the 

 human race, and appear to think that they have indicated a valid 

 objection. Probably it is a by-product correlated to mental evolu- 

 tion in general a by-product which was harmless while mind was 

 evolving, and only became injurious when men discovered that 

 certain vegetable poisons were capable of producing delightful 

 sensations. But the question as to how it arose is one thing. The 

 question as to whether it, being existent, is a cause of selective 

 elimination is quite another thing. It certainly exists. 



520. The theory that alcohol and opium, like lethal and pre- 

 valent diseases, are causes of protective evolution, is so opposed to 

 popular notions that it is apt to be received with initial incredulity. 

 I can only beg the reader to test the chain of fact and reasoning 

 link by link. I believe that he will conclude ultimately that, if 

 evolution has occurred in any instance, then it has occurred in this 

 instance also. Is it undeniable that men differ in the sensations 

 awakened in them by alcohol (and opium) ; that some are so consti- 

 tuted that after a given experience they are much more tempted 

 to excessive indulgence than others, for the reason that their 

 sensations are more pleasurable ; that, as a general rule, men yield 

 to temptation in proportion as they are strongly tempted ; that the 

 average moderate drinker shows no indication that he is strongly 

 tempted to deep indulgence ; that the average excessive drinker 

 shows every indication that he is so tempted, for otherwise no one 

 would do actions so painful and ruinous, both in the immediate and 

 remote future ; that he tends to transmit his degree of suscepti- 

 bility to descendants; that drink tends to shorten the lives of 

 excessive drinkers and otherwise lower the number of their possible 

 descendants ; that the amount of this elimination is large j that 



