352 THK PRESENT EVOLUTION OF MAN — MENTAL 



fore, the race is protected only by the inborn power of 

 making immediate resistance. 



In all this there is a close analogy between narcotics 

 and diseases. Against some narcotics — e. g. tobacco — the 

 individual, even of a race that is strange to them, easily 

 acquires immunity ; that is, the cells concerned (nerve- 

 cells) not only acquire the power of tolerating the 

 poison (toxin), but the craving for it is satisfied in the 

 individual by a limited and generally harmless degree 

 of indulgence; and therefore since such narcotics are 

 the cause of little or no elimination, they are the cause 

 of little or no evolution ; and races that have longest 

 experienced them, crave for indulgence in them as 

 greatly as races that have had little or no experience 

 of them. On the other hand, there are other narcotics 

 — e.g.dlc6ho\ — against which powers of making resistance 

 cannot be acquired to nearly so great an extent. For 

 instance, no man can tolerate alcohol to nearly such an 

 increased extent as he can nicotine, as a result of in- 

 dividual experience of it ; that is, no amount of indul- 

 gence can reproduce in the experienced smoker those 

 immediately poisonous effects of nicotine which his first 

 indulgence in tobacco produced, whereas a slight in- 

 crease of indulgence will reproduce in the drinker those 

 immediately poisonous effects of alcohol which he ex- 

 perienced when first he indulged in the poison. The 

 power of making resistance to alcohol, unlike the power 

 of making resistance to nicotine, is therefore mostly of 

 the inborn kind. The individual craving for it in races 

 not rendered resistant by evolution in the ancestry is 

 not satisfied by a degree of indulgence so limited that 

 it is generally harmless, but only by a degree of indul- 

 gence which is exceedingly harmful; and therefore, 

 since such narcotics are the cause of much elimination, 

 they are the cause of much evolution ; whence it follows, 

 that races that have longest experienced them crave 



