Botanical name: 

The seeds of Caffea arabica, Linné (Nat. Ord. Rubiaceae). Native of Arabia-Felix and Ethiopia; and extensively cultivated in Asia and America between the north and south latitudes of 56°.
Common Name: Coffee.

Principal Constituents.—The chief constituents are caffeine (C8H10N4O2.H2O); a volatile aromatic oil; caffeol is also present in minute quantity and upon it depends the aroma of coffee; and caffeo-tannic acid.
Preparations.—1. Infusum Caffeae, Infusion of Coffee. Dose, 2 to 8 fluidounces.
2. Specific Medicine Coffeae. Dose, 1 to 60 drops.
Specific Indications.—Feeble circulation, with threatened heart-failure; sense of exhaustion; headache, with cerebral hyperemia or congestion.

Action.—Coffee is a decided cerebral stimulant and energizer. It also increases reflex activity of the spinal cord. Used moderately it is a mild bitter stomachic, stimulating the appetite and facilitating digestion. There is reason to believe that it increases hepatic activity and it promotes peristalsis, thereby favoring a free action of the bowels. Coffee slightly accelerates the circulation. Under its use the intellect is quickened to an extraordinary degree, thinking is facilitated, ideas flow freely, the reasoning faculty is sharpened, and an enormous amount of mental and physical work may be accomplished. The action of hot coffee upon the cerebrospinal system is especially evident when a person is exhausted by mental strain or physical exertion. Coffee removes drowsiness after a heavy meal, and may produce wakefulness that will last for several hours. If coffee be withheld from one who is accustomed to its stimulus, physical and mental exhaustion become so severe as to interfere with intellectual pursuits or bodily endurance under exertion, and a profound headache may be experienced. Coffee probably retards tissue waste, and is, therefore, a conservator of force.

The excessive use of coffee causes irritability, dejection of spirits, muscular weakness and trembling, watchfulness, dizziness, headache, and ringing noises in the ears; and flatulence, sour stomach with heartburn and eructations, and disordered action of the bowels. Probably the hepatogastric symptoms—"coffee biliousness"—is due largely to the empyreumatic oil present in coffee; the nervous symptoms chiefly to the caffeine it contains. Therefore preparations from which the latter has been removed are just as likely to produce stomach disorders as regular coffee.

The stimulating effects of coffee are most largely due to caffeine. This alkaloid is one of the most rapidly acting cerebro-spinal stimulants and probably the nearest of any drug to a physiologic energizer of the intellectual brain. It sharpens the intellect wonderfully, and increases particularly the reasoning faculties rather than the imaginative. It operates without after-fatigue and renders the person capable of great mental achievement and physical endurance. Workmen do more work under coffee, and soldiers stand long marches under the stimulus of the caffeine it contains. Large doses produce excitation of the spinal cord, and if carried to full action exaggerate the reflexes, making the person exceedingly nervous. No harm, however, is done to any organ by coffee or by caffeine, and no after-fatigue or exhaustion follows, provided neither be given to the extent of interfering with the taking of food nor of preventing rest or sleep. Caffeine excites muscular contractility, and powerfully stimulates respiration. Upon the circulation it heightens blood pressure and quickens the contraction of the heart. These are accomplished through its action upon the vaso-motor control and upon the heart muscle itself, its effects upon the latter taking origin at the veno-auricular junction, and extending from thence to the auricle and the ventricle. Caffeine increases the output of both the solids and the fluids of the urine, by dilating the renal bloodvessels and by direct action upon the renal epithelia. The tissue-waste of the body is thought to be restrained by caffeine, thus making it a conservator of force and energy. Caffeine is believed to be oxidized and destroyed in the body. The common non-alcoholic beverages of mankind (except coca)—coffee, tea, cocoa, kola, maté and guarana—owe their grateful stimulus to caffeine or related alkaloids. The theine of tea is practically caffeine. All of them relieve fatigue, increase mental acuity, endurance and the capacity for exertion without being followed by fatigue or exhaustion.

Therapy.—Coffee in strong infusion is given both by stomach and rectum in opium poisoning. It should be made fresh and as strong as possible. The warmth adds to its efficiency. A cup of strong, hot coffee is often an effectual sobering draught in acute alcoholism. and small and repeated amounts will sometimes ward off an attack of delirium tremens. Coffee is a gratefully refreshing agent for headache due to cerebral hyperaemia or congestion, as shown by red face and injected eyes, but will be likely to aggravate a neuralgic headache when the face is pale. Strong coffee sometimes cuts short an attack of asthma, and checks hiccough. It is the most refreshing stimulant that can be used in the exhaustion of low fevers of a typhoid type and in the debility following other acute disorders, particularly if the patient was previously accustomed to its use as a beverage. In fact, coffee should never be wholly withheld in acute disorders when it has been a factor in the patient's daily dietary. For its stimulating effect in fatigue and nervous exhaustion and calming action in nervous excitation of debility, coffee should be freshly prepared and drunk hot, preferably without sugar or cream; for use in narcotic poisoning very strong, "black coffee" may be given freely, both by mouth and per rectum.

(I get the impression that the good Dr. Felter was fond of coffee—MM)

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