Among the widely varying classes of drug-users, three in particular are a source of the gravest danger: the drug-taking physician, nurse, and pharmacist. To realize this, one has merely to recall that the drug-taker is a confirmed evader of responsibility; and the physician, of all men, is in a responsible position. He must not forget or break his appointments; he must realize the effects of the medicines he is prescribing; if a surgeon, his work must never be below its best. But the proportion of physicians that I have treated, or consulted with, suggests one specially grave danger. It is a characteristic of the drug-taker, no matter who he is or how he acquired the habit, on the smallest excuse to advise others to take the drug whenever pain or fatigue gives the slightest occasion for it. While he grows callous to everything else, he has an abnormal sympathy with suffering. Thus it will readily be seen that there are few more dangerous members of society than the physician who is addicted to a drug. The fact that there are not more drug-taking doctors speaks volumes for the high character of the profession. The physician has such drugs constantly at hand. The more a man knows of their insidious action and the more he handles them, the more cautious he feels himself to be, and the more confident that he can discontinue the use of them whenever he chooses. Any fear that the layman may have of them is due less to the dread of being personally overcome than to the mystery which surrounds them; but for the physician they have no such mystery. Furthermore, by the nature of his calling he is peculiarly exposed to the need of such drugs. He is often under excessive physical and nervous strain not only because he is unable to arrange his work so as to prevent periods of too great pressure upon his time and strength, but also because in a unique manner he puts his heart into it.