Under ordinary circumstances morphia is the preferable opiate for the relief of insomnia. The sulphate is most frequently employed, but the acetate and the tartrate have been recommended on account of their supposed superiority in the formation of solutions that are unirritating and permanent in their character. The hypodermic method of administration forms the most prompt and efficient mode of procuring the effect of the medicine. It should be given in a dose of quarter of a grain about an hour before the time when sleep is desired. For some patients a longer time is necessary to develop its hypnotic effect. To children the hypnotic dose must sometimes be given at three o’clock in the afternoon in order to induce sleep at nine o’clock in the evening. As the effect of opiates is highly stimulant to the sweat-glands, and is often productive of nausea, it is advisable to associate atropine with morphine when thus given. For an adult the hundredth of a grain of atropine may be given with every quarter of a grain of morphine. The soothing and agreeable effects of morphia are thus intensified, while its disagreeable tendencies are reduced to a minimum. The injection should be made into the loose areolar tissue between the skin and the muscles. Its location is a matter of little importance so far as the relief of pain is concerned; but the neighborhood of the blood vessels should be avoided, since alarming symptoms have been observed after injection into a vein. The outer aspect of the arm near the insertion of the deltoid muscle is a favorite site for puncture. If, for any reason, the hypodermic use of morphia cannot be employed, it may be introduced into the rectum either in solution or in a suppository. The bowel should first be washed out with an enema of warm water; the opiate may then be introduced. The dose thus exhibited need scarcely exceed that usually given by the mouth; but, if the rectum is not previously cleansed, a double, or even triple, dose may be required. As an hypnotic morphia is chiefly useful in phthisis, in cardiac dyspnœa, in diseases of the stomach which cause insomnia, in fevers with prostration and delirium, in delirium tremens, in mania, and in the majority of painful or spasmodic diseases. If the patient be violently excited, the opiate should be combined with small doses of tartar emetic, ipecac, or tincture of aconite. But in the chronic diseases it is desirable to avoid its continuous administration, not only on account of the risk of creating the opium habit, but also by reason of the injurious effects of the drug upon digestion and nutrition. _Codeine_ is a mild hypnotic which may be used in doses about twice as large as those of morphine. It is expensive and not very efficient, but may be sometimes prescribed with advantage when moral considerations render the use of ordinary opiates inexpedient.