The Enepidermic Method consists in placing the medicine in simple contact with the epidermis, no friction being used to hasten its penetration. Chloroform and Oleic Acid solutions of the alkaloids pass by osmosis in this manner with comparative ease, but aqueous solutions act very slowly and alcoholic ones with great difficulty if at all.

The Epidermic Method consists in the use of friction to promote the passage of the medicament between the cells of the epidermis. Mercurial Ointment, Cod-liver Oil, and other fats, Oleates, etc., are used in this way for their local and systemic effects.

The Endermic Method obviates the difficulty of absorption through the cuticle by removing the latter through the agency of a blister, and then powdering the medicament over the surface of the denuded derma.

An ordinary cantharides-plaster, followed by a poultice to raise the blister, may be employed; but a quicker method is to place upon the skin a piece of lint soaked in Stronger Water of Ammonia, covering it with a watch-glass or a piece of oiled silk to prevent evaporation. The blister raises rapidly and should then be removed with scissors. Morphine, Atropine, Quinine and Strychnine, are the agents generally used in this manner, but the method is painful and unpopular.

Inoculation is the introduction of medicinal agents through the scraped or punctured skin by an operation similar to that employed for vaccination.

DOSAGE OF MEDICINES.

The Doses given throughout this book are for adults; for children the following rule (Young's) will be found the most convenient. Add 12 to the age, and divide by the age, to get the denominator of a fraction, the numerator of which is I. Thus, for a child two years old, 2+12 = 7, and the dose is one-seventh of that for an adult. Of powerful narcotics scarcely more than one-half of this proportion should be used. Of mild cathartics, two or even three times the proportion may be employed.

For Hypodermic Injection, the dose should be two-thirds or three-fourths of that used by the mouth; by rectum five-fourths of the same. Strychnine acts more actively when given per rectum than by the stomach.

Conditions which modify the action of medicines, and therefore affect their dosage, are-age, body-weight, temperament and idiosyncrasy, drug-habits, intervals between doses, time of administration, condition of the stomach, temperature of the body, cumulative drug-action, mode and form of drug-administration, disease, climate, race, etc.

Children bear Opiates badly:-but on the other hand they stand comparatively large doses of several other drugs; such being Ársenic, Belladonna, Calomel, Ipecacuanha, Squill, Rhubarb, and several other purgatives.

CLASSIFICATION OF MEDICINES.

In the present state of knowledge respecting the actions and uses of medicinal agents, no really scientific classification of these substances is possible. Some writers have adopted a system based on the natural relations of the various articles to each other, while many classify them according to their effects on the human system, and others make no attempt at arrangement but treat of them in alphabetical order. latter method has been followed in this work, from a conviction that every medicine should first be studied as an individual, both with respect to its physiological actions and its therapeutical applications. When the student has thus made himself familiar with the characteristic features of each article of the Materia Medica, he may begin, by comparing one with another, to seek acquaintance with their more delicate lights and shades. Some system of classification then becomes imperative as an aid to the memory, and as the titles of the groups to which the various agents belong in any physiological classification are also used to express their actions and uses, the following synopsis is inserted as an appropriate introduction to the section on Materia Medica and Therapeutics.

STIMULANTS AND SEDATIVES.

These are general terms employed in various classifications with very little discrimination.

Stimulant (stimulus, a goad),-is a term which is used in various senses when applied to medicinal agents. Alcoholic preparations, which are true narcotics, are commonly termed "stimulants," and the same expression is employed to designate any agent which excites the organic action of a part of the economy.

Diffusible Stimulants are those which have a prompt but transient effect, such as Alcohol, Ammonia, Camphor, etc. Spinal Stimulants exalt the functions of the cord, as Strychnine, Picrotoxin, Ergot, Atropine, Phosphorus. 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, Podophyllum, 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 anesthetics. 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 overstimulation.

The most important members of this class are Nux 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 respiratory 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.

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

* In large doses.

In small doses.

doses of Quinine; others by a directly paralyzant action on the centres. The principal members of this class may be enumerated as follows, viz. :—

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 of the sensory nerves in the skin, though some act probably by stimulating the local circulation, as in inflammation. The principal members of this group

Local Anæsthetics and Anodynes (av, without, alo0nots, perception, doŋ, 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 Anæs thetics destroy, for a time, the sensibility of the skin or mucous membrane. The chief agents of this class are

Local Anodynes.

Aconite, Aconitine.
Belladonna, Atropine.

Opium, Morphine.

* In large doses.

Local Anaesthetics.
Extreme Cold, Ice.

Ether Spray.
Carbolic Acid.

† In small doses.

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 are

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), and may be listed as follows, viz.

Alcohol.
Belladonna.
Stramonium.

Hyoscyamus.

Cannabis Indica.
Chloral.
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 (vápzŋ, 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