The difference between the psychology of the doctor's relation to the drug habit and that of the layman to it may be summed up in the statement that while the layman does not at all know what he is getting, the doctor knows what he is taking, but thinks that he can stop taking it whenever he feels ready. It is probable, therefore, that the doctor's primary danger is as great as the layman's, and it is certainly true that his secondary danger--that growing out of the fact that he has drugs and the instrument for their administration always ready to his hand--is very much greater. The unnecessary administration of habit-forming drugs to the sick must be legally prevented as far as possible. No affliction which can be added to an already existing physical trouble can compare in horror with that of a drug habit. Numbers of cases have come under my observation in which physicians have accomplished exactly this addition to the ruin of their patients' health, to the incalculable distress of the sufferers' families, and to the vast loss of society. In the recent legislation written upon the statute-books of New York State the first definite effort is made to provide against this catastrophe. CHAPTER IV PSYCHOLOGY AND DRUGS Drug habits may be classified in three groups: the first and largest is created by the doctor, the second is created by the druggist and the manufacturer of proprietary and patent medicines, and the third, and smallest, is due to the tendency of certain persons toward dissipation. The major importance of the first two groups is due to the fact that they include by far the greater number of cases, and to the pitiful fact that such victims are always innocent. Speaking generally, and happily omitting New York State from our statement, it is safe to say that the manufacturer, the druggist, and the physician are without legal restraint despite their importance as promoters of drug habits, while the comparatively unimportant drug-purveyor in the under-world is held more or less strictly in control by the police, and is subject to severe punishment by the courts in case of a conviction. With few exceptions, the part which the doctor plays in the creation of drug habits is due to lack of knowledge; but the druggist's part in the spread of this national curse is purely commercial, and may justly be designated as premeditated. He always has gone and always will go as far as is permissible toward creating markets for any of the wares that he sells.