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Cardiac Stimulants increase the action of the heart, as Alcohol, Atropine and Morphine in small doses, Strychnine, etc., also Squill, Convallaria, Cimicifuga and Digitalis, which slow but strengthen the cardiac action. Vaso-motor Stimulants, as Alcohol, Chloroform, Ether, Ammonia, Strychnine, Digitalis and Squill, acting on the vaso-motor centre; and the Nitrites, Belladonna, Electricity, Volatile Oils, etc., acting as local dilators of the vascular system. Cerebral Stimulants as Alcohol, Opium, Belladonna, Caffeine, Cocaine, Theine, Cannabis, Chloroform, Ether, Tobacco, etc. Renal Stimulants, as the diuretic group. Stomachic Stimulants, as the Aromatics, Volatile Oils, Vegetable Bitters, Mineral Acids, Nux Vomica, Mustard, Capsicum, etc. Hepatic Stimulants, as Nitro-muriatic and Nitric Acids, and the cholagogue purgatives Podophyllum, Jalap, Leptandra, Euonymin, Iridin, etc. Intestinal Stimulants, as Mercurials, Elaterium, Colocynth, Jalap, Scammony, Podo. phyllum, etc., which affect the glandular apparatus,-and Belladonna, Physostigma, Nux Vomica, Rhubarb, Senna, Aloes, Frangula, Cascara, etc., which chiefly affect the muscular fibres and the intestinal nerves. Cutaneous Stimulants, as the diaphoretic group, and the rubefacients Mustard, Capsicum, Turpentine, Ammonia, etc. All stimulation reacts into depression, and most of the agents which stimulate the nerve centres at first soon depress and finally paralyze them.
Sedatives (sedo, to allay),—are agents which exert a soothing influence on the system by lessening functional activity, depressing motility and diminishing pain.
General Sedatives include the narcotics and anästhetics. Local Sedatives include Aconite, Opium, Ice, etc. Pulmonary Sedatives, as Hydrocyanic Acid, Veratrine, and the nauseants and emetics. Spinal Sedatives, as Physostigma, Gelsemium, Potassium Bromide. Stomachic Sedatives include Arsenic, Bismuth, Nitrate of Silver, Bicarbonate of Sodium. Vascular Sedatives, as Digitalis, Tobacco, Aconite, Veratrum, and the emetics. Nervous Sedatives, among which are Potassium Bromide, Tobacco, Lobelia, and the group of spinal depressants.
AGENTS ACTING CHIEFLY ON THE Nervous SYSTEM.
Motor-Excitants are agents which increase the functional activity of the spinal cord and the motor apparatus, producing disturbances of motility, heightened reflex excitability, and tetanic convulsions when given in large doses, their ultimate effect being motor paralysis from over-stimulation.
The most important members of this class are Nur Vomica and Ignatia, with their alkaloids Strychnine and Brucine, also Thebaine, the tetanizing alkaloid of Opium. It also includes Morphine and Atropine, which, though at first sedative, when given in large doses produce convulsions. The respi. ratory centre in the medulla is stimulated by Strychnine, Atropine, Ammonia, and small doses of Alcohol, Ether and Chloroform. The motor convolutions in the brain are stimulated by Alcohol in moderate doses, as also for a brief period by Ether and Chloroform.
The end-organs of the motor nerves are stimulated by the local use of Electricity, Strychnine and friction; and are irritated by the internal administration of Aconitine, Nicotine, Camphor, Pilocarpine and Pyridine. Other members of this class are embraced in the following list. Nux Vomica. Alcohol.t
Rhus Toxicoden. Atropine.*
Calabarine. Camphor. Electricity.
Motor-Depressants lower the functional activity of the spinal cord and motor apparatus, and in large doses paralyze them. Some act indirectly by reducing the spinal circulation, as Digitalis, Aconite and large doses of Quinine; others by a directly paralyzant action on the centres. The principal members of this class may be enumerated as follows, viz. Opium, Morphine. Curare.
Ergot (at last). Ethyl Strychnine.
Other Methyl Compounds.
Ethyl Ammonium Chloride.
Amyl Ammonium Chloride. Camphor. Lithium.
Amyl Ammonium Iodide. Aconite. Zinc.
Amyl Ammonium Sulphate. Tobacco. Prussic Acid.
Other Compound Ammonias. Lobelia.
Potass. Cyanide. Galvanism. The motor centres in the medulla are powerfully depressed by Opium, Morphine, Aconite, Conium, Chloral, Physostigma, and large doses of Alcohol, Ether and Chloroform. The three last named are also paralyzers of the motor convolutions in the brain, arresting all voluntary movements when administered in sufficient quantity. The anterior cornua of the cord are greatly depressed by Physostigma and other agents, and the motor nerves by Conium, Methyl-Strychnine, etc., both actions resulting in paralysis of the limbs. Curare, even in small doses, paralyzes the end-organs of the motor nerves, and Belladonna, the compound Ammonias, Methyl compounds, etc., exercise a similar but less powerful influence. Galvanism is also an effective local depressant of motor activity.
Local Stimulants increase common sensibility to the extent of producing pain, chiefly by direct action upon the end-organs
* In large doses.
† In small doses.
of the sensory nerves in the skin, though some act probably by
Acrid Essential Oils.
Veratrine (at first).
Cantharis (at first).
Local Anæsthetics and Anodynes (av, without, ažo0701, perception, öðuvn, pain),–reduce the functions of the sensory nerves until they lose the power of receiving or conducting sensations. Some act by direct depression of the end-organs in the skin, etc., others by impairing the conductivity of the sensory nerves, while some act indirectly by reducing the local circulation. The Anodynes diminish, and the Anästhetics destroy, for a time, the sensibility of the skin or mucous membrane. The chief agents of this class areLocal Anodynes.
Extreme Cold, Ice.
Oil of Turpentine.
Cerebral Excitants,-are remedies which increase the functional activity of the cerebrum, without producing any subsequent depression, or any suspension of the cerebral functions. They act partly by increasing the action of the heart and consequently the rapidity of the circulation, partly by a direct action upon the gray matter of the brain. The chief members of this group areAlcohol (at first).
Acetic Acid (inhaled).
Deliriants excite the functions of the higher brain to such a degree as to disorder the mental faculties, producing intellectual confusion, loss of will-power, delirium and even convulsions.
They are all narcotics (though all narcotics are not deliriants),
Lupulus (at first).
Opium (at first).
Cerebral Depressants lower or suspend the functions of the higher cerebrum after a preliminary stage of excitement. Under this head may be included the Narcotics, General Anæsthetics, and several of the Antispasmodics, all acting on the cells of the convolutions, at first stimulating the brain-functions, they produce after a time stupor, coma and insensibility.
The most useful of this class are the Bromides, Zinc and Caffeine, as they also diminish reflex excitability and thus secure rest of the nervous system. Some of them are decidedly dangerous, as they may paralyze the heart or the medulla and its centres of organic life before the consciousness is much disturbed; such being Chloroform, Aconite, Opium, and the irritant poisons.
Narcotics (vápx, stupor),-are agents which, at first excitant to the higher brain, produce profound sleep, characterized by stupor, and if the dose be sufficient coma, insensibility and death by paralysis of the medullary centres governing respiration and other functions of organic life. They are closely related to stimulants, Opium and Alcohol being good illustrations, in the different stages of their action, of both stimulant and narcotic effects. They give us the power of lowering perception, inducing sleep and soothing the vital functions by rest, all of which are means of great therapeutical value. The chief narcotics areAlcohol.
Chloroform, Ether, etc.
Hypnotics (ů Tvos, sleep), -are remedies which produce sleep, and in this wide sense of the term the class would include the Narcotics and the Anästhetics, as well as those agents which may be termed Pure Hypnotics, which induce sleep by bringing the brain into a favorable condition therefor rather than by direct soporific action. In this sense the purest hypnotics are the Bromides, but artificial sleep may be produced by many other agents. The principal members of this class are the following:
Opium, Morphine, Narceine.
Analgesics (av, without, älyos, pain), or Anodynes (av, without, oùóvn, pain), -are remedies which relieve pain, either by direct depression of the centres of perception and sensation in the cerebrum, or by impairing the conductivity of the sensory nerve fibres. Opium is the most efficient of all analgesics, because it arrests the afferent impressions at every step of their track—at their formation, along the course of their conduction, and at the point where they impinge on the sensorium.
The Local Anodynes have been described (ante, page 402), and
Chloroform, Ether, etc.
Anæsthetics (dy, without, a?o07015, perception),-are agents which destroy sensation. Local Anæsthetics have been described (ante, page 402.) General Anæsthetics are certain volatile substances, mostly belonging to the class of alcohols and ethers, which when inhaled produce complete unconsciousness and loss of sensation (anæsthesia), with lessened motor power.
Narcotics also produce anästhesia, but the term is usually restricted to the effects of the volatile agents referred to, a full list of which may be found on pages 45 and 140. The principal members of this group areEther (Oxide of Ethyl).
Bromide of Ethyl.
Bichloride of Ethylene.
Antispasmodics (àvtí, against, onaowós, a spasm),--are agents which prevent or allay spasm of voluntary or involuntary muscles in any portion of the organism. Some of the agents belonging to this class act by stimulation of the higher nervous centres, the