Botanical name: 

The dried flowering tops of the female plant of Cannabis sativa, Linné, or the variety indica, Lamarck (Nat. Ord. Cannabinaceae). Asia, East Indies, and cultivated in other parts of the world, notably in the United States.
Common Names: Guaza, Ganjah, Gunjah, Ganga; Indian Hemp (Cannabis indica) when derived from the Indian plant.

Principal Constituents.—Not well determined. The following have been noted: Cannabin, an active brown resin, and cannabinon, a soft resin.
Preparation.—Specific Medicine Cannabis. Dose, ½ to 10 drops.
Specific Indications.—Marked nervous depression; irritation of the genito-urinary tract; burning, frequent micturition; painful micturition, with tenesmus; scalding urine; ardor urinae; wakefulness in fevers; insomnia, with brief periods of sleep, disturbed by unpleasant dreams; spasmodic and painful conditions, with depression; mental illusions; hallucinations; cerebral anemia from spasm of cerebral vessels; palpitation of the heart, with sharp, stitching pain; and menstrual headache, with great nervous depression.

Action.—The principal seat of action of cannabis is upon the intellectual part of the cerebrum. In many respects its effects parallel those of opium and its chief alkaloid. Without doubt it is the most perfect psychic stimulant known to medicine. Certain Orientals become addicts to it, consuming it in the form they call haschisch (whence comes the term assassin), and under its influence many crimes and offenses have been committed, as well as with it. Eastern potentates are said to have dosed their fanatic followers with it. It produces an agreeable semi-delirium taking on the character of a sense of well-being and exhilaration-a state highly coveted by its devotees, who call it loftily "the increaser of pleasure," "the laughter mover," "the cementer of friendship," and "the cause of a reeling gait"-all indicative of its physiologic influence. These haschisch debauches are joyful affairs, and while usually devoid of injurious consequences, may be followed by catalepsy and depressive and maniacal insanity, from which, however, the victim recovers fully in time.

In some respects the effects of cannabis on the nervous system are peculiar. It causes an apparently contradictory, consentaneous stage of stimulation and depression-a state somewhat simulated by morphine. The sensations that follow the effects of cannabis vary greatly with the temperament and the peculiarities of the patient, and with his environment. Almost invariably they are pleasurable. An emotional state of happiness even to ecstasy is experienced, with an endless procession of beautiful visions coming and going, and over which the patient indulges in merriment and even hilarity. So pleasurable becomes his sensations that he may break into boisterous laughter and antics of a ridiculous character, the nature of which he fully comprehends, but is wholly unable to prevent. Gradually passing into a dream-like stage, he talks, volubly, brilliantly, with ever-recurring changes of topic, little coherence of thought, and a perverted judgment. His imagination carries him into ludicrous ideas and strange actions, he has notions of grandeur and greatness, and moments are exaggerated into aeons of time. He lives a "life-time in a minute." Endless phantasms of beauty and delight pass before his distorted mental vision. A singular peculiarity is a state of "double consciousness" or dual personality which possesses him in which he imagines he is both himself and some one else, and he behaves accordingly. He becomes affectionate to the extreme, both to himself and to others, and altogether he is a very happy individual leading a very full and infinitely extended life.

Finally drowsiness overtakes him and he drops into a heavy sleep, which may last for hours, and from which he awakens with no other discomfort than a ravenous hunger. In this last stage the pupils are dilated, muscular power in abeyance, and partial anesthesia prevails. While the ultimate effects of the drug in some result in tremor, great weakness, loss of appetite and convulsions, no deaths have been known to occur in man from this drug.

The effect upon Caucasians is less pronounced than that described, which is experienced chiefly by Orientals. In the former the stage of exhilaration and phantasmagoric inebriation may be very brief or entirely absent, the patient passing successively through heaviness and numbness of the limbs, heat in the head, giddiness, a pleasurable pricking of the whole body, drowsiness, and deep sleep. With some individuals pressure upon the skin is said to excite a sense of burning, and the subsequent anesthesia may become so profound that the patient, when standing, is not conscious of contact with the ground.

One young man to whom we administered cannabis amused himself by repeatedly jumping over the foot of his bed, laughing with great glee over his capers.

Therapy.—The therapeutic effects of cannabis vary under different conditions. It stimulates in depression and sedates when there is irritation. It lessens pain-especially spasmodic pain-allays spasm, improves the appetite, causes a feeling of contentment and rest, and produces sleep. If pushed too rapidly or in too large doses, exhilaration of spirits, inebriation with phantasms, illusory delirium, and sometimes strong aphrodisia precede sleep. A peculiarity in many individuals taking cannabis is the voracious appetite induced. The effects of cannabis are far less powerful and less disturbing to the general system than those of opium, and it does not, like the latter, restrain the secretions nor produce itching. If anything the urine is increased by cannabis and constipation does not occur.

The keynote indication for cannabis is marked depression of the nervous system usually with insomnia. Secondly, it allays irritation of the urino-genital tract and relieves pain. For the first condition it is invaluable in more or less painful conditions in which opium seemingly would be indicated, but in which, on account of its tendency to restrain normal secretions, would be inadmissible. In fact, cannabis exerts far less restraining power over the secretions than do most similar anodynes. Besides, it favors good digestion and dispels gloom and foreboding. As a pain reliever it is more potent than as a sleep producer, as for some unknown reason even good qualities of cannabis often fail in insomnia when they succeed perfectly in blunting pain. As a remedy for pure insomnia without pain it is less valuable than many other hypnotics. It is, however, often useful in the sleeplessness of depressive insanity.

Depressive headache, particularly migraine, is one of the types of pain in which cannabis is exceedingly effective. Its use is often advantageously preceded by gelsemium. These cases are those that come on with much excitability and hyperaemia, followed by depression. It is in the depressive stage that cannabis is useful. Spasmodic neuralgic pains are helped by it. It is particularly indicated in the vague pains of indigestion, in depressive nervous headache, nervous gastralgia, gastric neuralgia, gastric ulcer and carcinoma (in the latter two, when opium disagrees), the pains of irritative diarrhea, neuralgia of the face, neuralgia of the pelvic viscera, so-called chronic rheumatism, endometritis, subinvolution, after pains, and amenorrhea, all with nervous depression and despondency. It is sometimes useful in the painful paroxysms of locomotor ataxia and sciatica, but as a rule is not powerful enough to subdue these and the severe cramp colic induced by the passage of calculi, unless given in doses large enough to produce other unpleasant effects. Morphine is by far the better agent for the relief of pain in renal and hepatic colic. Cannabis gives relief in painful and spasmodic dysmenorrhea, marked by much nervous debility; and it is accredited with having promptly checked functional menorrhagia.

Cannabis is a remedy for convulsive and irritative forms of cough. It is especially comforting in the latter stages of phthisis and for the cough of senility, with senile catarrh. In both instances the cough is harassing, expectoration heavy and difficult, and rest and sleep are disturbed. While effective in whooping cough there are better agents for use in children than cannabis. Cannabis aids in depressive hysteria; quiets excessive movements in paralysis agitans, and in some cases of chorea; and sometimes quiets a palpitating heart. It relieves itching in many skin disorders, and especially the pruritus of the aged.

It is, perhaps, in genito-urinary disorders of a subacute and chronic inflammatory type that the usefulness of cannabis is most strongly displayed. With the properly-selected sedative it meets the wants of a pain reliever and nerve soother in urethritis, whether idiopathic or specific. Gelsemium, aconite, and cannabis are, perhaps, more frequently indicated than other internal agents in acute gonorrhea. Locke invariably prescribed the following: Rx Specific Medicine Aconite, 10 drops; Specific Medicine Cannabis, Specific Medicine Gelsemium, 1 drachm each; Simple Syrup and Water enough to make 4 fluidounces. Mix. Sig.: One teaspoonful every three hours. This relaxes spasmodic tension, relieves ardor urinae, reduces fever and inflammation, and does much to prevent chordee, and to control it when present. In chronic nephritis cannabis is useful when there is much pain in the back and when blood is passed in the urine. Cannabis is sometimes useful in spermatorrhoea when accompanied by worry, gloomy foreboding, and general mental and physical depression. Having some aphrodisiac action it may be given with strychnine to restore sexual power lost through excesses, but not when due to organic changes. It is of supreme importance in surgical fever due to the passing of the catheter or bougie, or from operations upon the urethral tract. In chronic cystitis, chronic irritation of the bladder, dysuria, painful micturition, and strangury, it is a drug of very great value. In all instances a good preparation of cannabis must be used, for a poor quality is worse than useless.

The Eclectic Materia Medica, Pharmacology and Therapeutics, 1922, was written by Harvey Wickes Felter, M.D.