THE PRESENT EVOLUTION OF MAN — MENTAL 355 



of toleration ; for in the latter case the individuals of one 

 generation would as effectually j^oison themselves with 

 larger doses, as did the individuals of preceding genera- 

 tions with smaller doses. 



In fact, evolution against alcohol and opium tends to 

 place the race in the same position as regards them as 

 it already holds in relation to nicotine ; that is, it tends 

 to bring about such a diminution of the depth of the 

 intoxication desired that the individual is no longer 

 placed at a disadvantage in the struggle for existence 

 by reason of his craving : but in the case of opium, the 

 narcotic in relation to which the individual is himself 

 able to undergo a great protective reaction, this evolu- 

 tion appears much easier of achievement than in the 

 case of alcohol, the narcotic against which the individual 

 is able to undergo comparatively little protective reac- 

 tion ; for while the evolution against alcohol, as we have 

 seen, is only perfected after the lapse of many centuries 

 of stringent Alcoholic Selection, the evolution against 

 opium appears to be perfected, as we shall see, in a 

 much shorter space of time — in quite a few centuries. 

 It appears, therefore, that in the case of opium, the nar- 

 cotic which resembles nicotine, in that it is a toxin, and 

 in that the individual reaction to it is great, the race 

 with comparative ease achieves a position in relation to 

 it similar to that which it holds in relation to nicotine ; 

 but in the case of alcohol, the narcotic which is dissimi- 

 lar from nicotine in that it is a waste product, and in 

 that the individual reaction to it is comparatively little, 

 the race achieves a like position in relation to it only 

 with great difficulty and after many centuries of selec- 

 tion. In fact, efficient protective evolution against 

 opium appears to result from a much smaller divergence 

 from the susceptible ancestral type than does efficient 

 protective evolution against alcohol. 



It has already been remarked that, after having con- 



