Page:George Archdall Reid 1896 The present evolution of man.djvu/366

In the effects produced by it, both on the individual and on the race, opium appears to lie midway between tobacco and alcohol. As in the case of nicotine, experience of it by the individual induces a great protective reaction—enables the individual to tolerate immensely larger doses of the poison—but this protective reaction, this power of acquiring immunity, is not so complete in the case of opium as it is in the case of nicotine, since increased indulgence in the former may reproduce even in the most experienced individual those symptoms of immediate poisoning which indulgence in it first produced. At the least this is true; that while habitual indulgence in tobacco tends to cause, even in individuals of a race that has had no experience of it, a protective reaction, in consequence of which the individual no longer craves for indulgence in it to such an extent as to reproduce the symptoms of immediate poisoning which he felt when first he indulged in the poison, habitual indulgence in opium by individuals of a race that has had no experience of it, very rarely results in a protective reaction of such a nature that the individual no longer craves for indulgence in it to such an extent as to reproduce those symptoms of immediate poisoning which he felt when first he made the acquaintance of the narcotic. On the contrary, such an individual, notwithstanding the protective reaction he undergoes, whereby he is enabled to withstand increased doses, yet generally craves for indulgence to such an extent as to reproduce the symptoms of immediate poisoning; and therefore—as in the case of alcohol—indulgence in opium to the full extent of his desire tends to bring about his elimination; whence it follows that opium, like alcohol and unlike tobacco, is a cause of evolution—an evolution which is mainly from a greater craving towards a lesser craving, not mainly from a lesser power of toleration towards a greater power