Certain dangers inevitably arise where an intimacy exists between doctor and patient, since few physicians are morally so constituted that they will order a prosperous patient to do this or that or find another physician. In other words, instances have not been uncommon where the toleration of physicians for unfortunate practices among their patients has had its basis, and perhaps one not entirely inexcusable in these days of high pressure from professional competition, in self-interest. Social relations also have often led physicians to tolerate practices that they knew to be harmful to their patients and to the community. A patient who is a member of an influential club or a fashionable church is likely to be an asset of exceptional value to the physician whom he patronizes, for he is likely to recommend him to his friends. Good business management on the physician's part leads him to keep such a patient good natured and comfortable, and to keep him comfortable means, among other things, to keep him free from pain. Where the patient suffers from an incurable malady, the use of drugs is not only excusable, but commendable; but instances are all too frequent where the malady is not incurable, but only puzzling and beyond the average practitioner's power of diagnosis, so that he covers up his ignorance by the administration of pain-deadening substances. Patients who invariably and promptly pay their bills are sometimes in a position where they can tell a doctor what to do; whereas it should be the doctor's unalterable resolution to retain the upper hand. Instances of this kind are far less grave in connection with the use of alcohol than in connection with the use of drugs; the physician may be said almost never to play any part in the establishment of an alcoholic habit among his patients, while he has surely played a most important part in the spread of drug habits. CHAPTER XII CLASSIFICATION OF HABIT-FORMING DRUGS Opium is the basis of almost all the habit-forming drugs. There is no other drug known to the pharmacist that has a similar action or can be used as a substitute when a definite tolerance of it has been established. The chemists have given us more than twenty different salts or alkaloids of opium in various forms and under as many different trade names, and I regret to say that they are busy working in their laboratories to put upon the market injurious drugs under various supposedly harmless disguises, but intended in the end only to deceive. MORPHINE Morphine is the active principle of opium, and until a few years ago only crude opium or morphine was used for medical requirements. Morphine is intrinsically far worse than opium itself, for opium has certain properties which partly counteract the effect of the morphine that it contains. But morphine is not only the active principle, but the actively evil principle, of the drug.