Frequent intoxication with alcohol, opium, coca, or haschisch, brings about a structural degeneration of the nerve-material; the consequences of which are to be seen in delirium, softening of the brain, and other forms of general paralysis. "By degrees the nervous centres, especially those on which the particular narcotic used has the most powerful influence, become degraded in structure." A permanent pathological state is thus induced, in which the production of a given narcotic effect is not so easy as in the healthy organism. "A certain quantity of nervous tissue has in fact ceased to fill the _rôle_ of nervous tissue, and there is less of impressible matter upon which the narcotic may operate, and hence it is that the confirmed drunkard, opium-eater, or _coquero_, requires more and more of his accustomed narcotic to produce the intoxication which he delights in. It is necessary now to saturate his blood to a high degree with the poison, and thus to insure an extensive contact of it with the nervous matter, if he is to enjoy once more the transition from the realities of life to the dreamland, or the pleasant vacuity of mind, which this or the other form of narcotism has hitherto afforded him."[8] It is easy to see how this structural degeneration may be produced. It takes a certain time for the nervous system to recover from the effects of each separate narcotic dose; and if a fresh dose is taken before recovery is completed, it is obvious that the diseased condition will by and by be rendered permanent. The entire process of nutrition will adapt itself gradually to this new state of things; and no efficiency of repair will afterward make the nervous system what it was before. It is in this way that the narcotic craving for continually increased doses is originated and kept alive. [8] See Anstie, op. cit. pp. 215, 216, 218.