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AGENTS ACTING ON THE CUTANEOUS SURFACE.

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Galactagogues (galla, milk, ago, I bring away),--are medicines which increase the lacteal secretion, as Ricinus, Tea, Anise, Fennel, Potassium Chlorate, etc. The value of many so-called galactagogues is extremely doubtful, the best being the local application of the leaves of the Castor-oil plant (Ricinus communis), and a good black Tea internally, with Milk, Beer or Porter as a beverage. Pilocarpus comes the nearest to being a true galactagogue, but its influence is very transient. pare LACTATION in Part III.)

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AGENTS ACTING ON THE CUTANEOUS SURface.

Irritants are substances which, when applied to the skin, produce a greater or less degree of vascular excitement. When used to produce a reflex influence on a part remote from their site, they are termed COUNTER-IRRITANTS, and may be subdivided into the following groups, viz. :—

Rubefacients (Rubefacio, I make red),-produce temporary redness and congestion of the skin, unless left too long in contact with the surface, when they may cause exudation between the cuticle and the true skin (vesicants), or may destroy the tissue and form a slough (escharotics). They may induce muscular atrophy.

Vesicants, Epispastics or Blisters,-produce decided inflammation of the skin, and outpouring of serum between the epidermis and derma. Cantharides is the agent generally used for this purpose.

Pustulants,-affect isolated parts of the skin, as the orifices of the sudoriferous glands, giving rise to pustules.

The following list embraces the principal agents and measures belonging to these groups, viz. :—

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Escharotics or Caustics (eskahrah, a slough or scab; kaioh, I burn), are agents which destroy a tissue to which they are applied, and produce a slough. They act usually in one of three modes, viz. :—

1. By abstracting the water of the tissue.

2. By combining with the albumen of the part.

3. By corrosive oxidation.

The principal escharotics are enumerated in the following list, the numbers affixed to each pointing out its mode of action as stated above.

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Astringents (ad, to, stringo, I bind),—are agents which produce contraction of muscular fibre and condensation of other tissues, the first probably by direct irritation, the second by precipitating its albumen and gelatin. They also lessen secretion from mucous membranes. principal astringents may be enumerated as follows, viz. :

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Bismuth Subnitrate, etc.
Cadmium Sulphate.
Copper Sulphate.
Ferric Chloride.

Lead Acetate.

Silver Nitrate.

Zinc Sulphate.

Sulphuric Acid, Gallic Acid and Acetate of Lead are examples of Remote Astringents, acting on internal organs through the blood. Those which affect the part to which they are applied are Local Astringents, and include most of those enumerated above.

Styptics and Hemostatics (steuphoh, I contract; haimah, blood; stahsis, a standing),-are agents which arrest hemorrhage, Styptics being those which are applied locally, and Hemostatics those which are administered internally. Some of the former act mechanically, by promoting the formation of a clot in the mouths of the bleeding vessels; others cause the vessels themselves to contract, checking the flow of blood. The principal members of this class are the following-named :

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Emollients (Emollio, I soften),—are substances which soften and relax the tissues to which they are applied. They relieve tension, dilate vessels, diminish pressure on the nerves, and protect inflamed surfaces from the air and from friction. The principal articles which may be classed under this heading are the following:

Hot Fomentations.
Poultices.
Glycerin.

Lard.

Linseed Oil.
Olive Oil.
Spermaceti.
Almond Oil.

Petroleum.
Soap Liniment.
Starch.

Cacao Butter.

AGENTS ACTING ON MICROBES, GASES, FERMENTS.

51 Demulcents (Demulceo, I soothe),-are substances generally of a mucilaginous nature, which soothe and protect the parts to which they are applied. This term is generally used for substances employed for mucous membranes, and the term Emollients for similar agents used on the skin. The chief agents belonging to this class are:

Acacia.

Cetraria.

Barley.

Liquorice.

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Protectives, are agents of a mechanical nature employed to cover and protect an injured part from the air, water, etc. Collodion and Gutta-percha are those in general use, but certain plasters, as the Adhesive, the Lead or the Soap Plaster, may be employed for this purpose, also Cotton Wool.

AGENTS ACTING ON MICROBES, GASES, FERMENTS, ETC. Antizymotics (anti, against, zeumohsis, fermentation),—are agents which arrest fermentative processes, which may depend upon the action of organic ferments (enzymes), as diastase, ptyalin, pepsin, etc., or upon that of organized ferments, as the yeast-plant, bacteria, etc. The Antizymotics may be subdivided into two groups, Antiseptics and Disinfectants. Antiseptics (anti, against, sayptekos, putrefaction), -prevent or retard septic decomposition, by destroying the bacilli which produce it, or by arresting their development. The chief antiseptics are:

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Disinfectants destroy the specific germs of communicable diseases, many of which belong to the microbe class, hence many antiseptics are also disinfectants. They act in several modes, some as oxidizants, others by combining with albumen, others by chemical combination forming. substitution-compounds, others by arresting molecular changes, and still others by altering the reaction of the media containing the germs. The principal disinfectants are:

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Condy's Fluid is an aqueous solution of Potassium Permanganate, 2 parts in 100, or gr. 176 in 3xx. Burnett's Fluid is a solution of Zinc Chloride, containing about 50 per cent. of the salt, and equivalent to the official Liquor Zinci Chloridi. Labarraque's Solution is the official Liquor Soda Chloratæ.

Deodorants, are agents which destroy foul odors. The Volatile Deodorants are chiefly oxidizing and deoxidizing substances, acting chemically on the obnoxious gases; while the Non-volatile ones are mainly absorbents, which condense and decompose the effluvia. The deodorants in general use are the following named :

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Charcoal.
Earth, Lime.
Ferrous Sulphate.

Parasiticides (parrahseetos, a parasite, cado, I kill),-are agents which destroy the animal and vegetable parasites found upon the human body. They are generally applied in the form of lotions, ointments or oleates, and include the following substances, viz.:

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Antidotes and Antagonists are terms frequently confounded with each other, and rarely defined with sufficient lucidity to enable a clear distinction to be drawn between them. An Antidote is a substance which affects a poison either physically or chemically, or both, and in such a manner as to remove the poison from the body or to form with it an insoluble salt or an inert compound, with the object of preventing its toxic action upon the organism.

Thus, Tannic Acid is an antidote to Digitalis, as it forms therewith a compound (tannate), which is soluble with difficulty and therefore comparatively innocuous. But as this tannate is not wholly inert, another antidotal measure must be employed, viz.:evacuation of the stomach, which may be accomplished by the administration of Zinc Sulphate or any other emetic, or by the use of a stomach pump.

Antagonists, on the other hand, are agents which directly oppose each other in some or all of their physiological actions, and may be used against each other to counteract their effects on the system. Antidotal action takes place in the alimentary canal, and is applicable to vegetable as well as mineral poisons. Antagonism takes place in the blood and tissues, and so far as antagonistic drugs are concerned, is applicable almost wholly to vegetable poisons, as these produce their effects after absorption. The heart and respiratory apparatus are the principal objective points for the antagonism of drugs, but the spinal cord, the cerebrum, muscular tissue and the glandular system are also affected by most of them.

Antagonistic Measures are such proceedings as may tend to antagonize certain effects of poisons, and include Artificial Respiration,-Faradism of the respiratory muscles,-Constant motion,-Douching,-Rest, etc.

AGENTS ACTING UPON EACH OTHER.

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Thus, to refer to the case of Digitalis again, Saponin and Senegin are its most complete physiological antagonists, their counteraction extending throughout the whole range of its effects. Aconite and Morphine antagonize its cardiac action, the former being considered the best antagonist to the effects of large doses, and the latter to those of its long-continued use. Alcohol is also indicated in Digitalis-poisoning, and absolute Rest in the recumbent posture is an antagonistic measure of great importance, by reason of the liability of the heart to cease its action on assuming the erect position, when much lowered by the drug.

In the treatment of poisoning, whether from mineral or vegetable substances, the first indication is to administer the appropriate chemical antidote, so as to render the poison harmless or comparatively so. Next, the stomach should be emptied and washed out, lest the newly-formed compound be absorbed after a time, and to remove any of the poison which may have escaped the action of the antidote. Next, the antagonist should be administered, in order to counteract the effects of such portion of the poison as may have been absorbed. Lastly, the appropriate antagonistic measures should be employed to sustain the action of any organic function which may show signs of failure. In most cases of alkaloidal poisoning absorption has proceeded so far before assistance is obtained that antidotes are of no value, and reliance can only be placed upon the physiological antagonist and such supporting measures as will tend to maintain vitality until the poison has been eliminated by the natural channels.

In the following pages the antidotes and antagonists for each poisonous substance in the Materia Medica are enumerated under their proper titles, and in the Appendix the same agents are tabulated in a suitable form for reference. A few examples are appended below, to illustrate the principles above stated, and to point out some of the most prominent instances of physiological antagonism at present known.

Atropine, Belladonna, etc.

Antidotes,-Tannic Acid, to form an insoluble tannate. Zinc Sulphate, as an emetic, or Apomorphine hypodermically, or the stomach-pump. Purgation. Antagonists,— Muscarine. Physostigmine. Pilocarpine. Morphine. Quinine. Aconite. Antagonistic Measures,—Artificial respiration. Faradism of respiratory muscles.

Strychnine, Nux Vomica and Ignatia.

Antidotes, Animal Charcoal suspended in water. Emesis, as above-mentioned. Antagonists, Chloral, or Chloroform, to muscular relaxation. Curare. Nitrite of Amyl. Bromide of Potassium. Antagonistic Measures,-Artificial respiration. Perfect quiet.

Morphine and Opium.

Antidotes,-Emesis or stomach-pump. Antagonists,-Atropine. Strychnine. Black Coffee. Caffeine. Ammonia, inhaled. Amyl Nitrite. Antagonistic Measures,—Cold douche. Artificial respiration. Continued movement.

Potassium Cyanide.

Antidotes,-Sulphate of Iron, to form Prussian Blue. Emesis.

pine. Ammonia.

Antagonists,—Atro

Alcohol. Antagonistic Measures,-Artificial respiration. Faradism.

Arsenic and its Compounds.

Antidotes,-Hydrated Oxide of Iron. Dialyzed Iron. Magnesia. Chalk. Lime-water. Emetics, or stomach-pump. Oil or Mucilage to protect the mucous membranes. Diluents. Iodide of Potassium, to promote elimination. Antagonists,-none.

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