THERAPEUTIC CATEGORIES IN 1868 FROM

THE ESSENTIALS OF MATERIA MEDICA AND THERAPEUTICS

By
ALFRED BARING GARROD, MD, FRS.

Fellow of the Royal College of Physicians; Professor of Materia Medica and Therapeutics at King's College, London;
Physician to Kings College Hospital; and Examiner in Materia Medica at the University of London.

3rd Edition
Revised and Enlarged by James Walton,
Bookseller and Publisher to University College,
137 Gower Street. 1868.

Introduction

The classification shown below comes from a period when medical men sought to emulate Linnaeus's work on plants and classify diseases and medicines in terms of order and classes.  I have altered Garrod's numbering system to try to make the system clearer, using only Arabic numerals.  I would like to thank Dr. Alun Davies for lending me his copy of this book.

THERAPEUTICS

Medicines have been very differently classified, at different times, by authors on Materia Medica and Therapeutics; some adopting a chemical and natural historical division, as is the case with the previous part of the present volume; others a physiological and therapeutic classification.  For the purpose of rendering a complete account of the action and use of each medicine, the former method is, doubtless, the more convenient and instructive, as all the facts pertaining to the action of individual drugs are thereby brought before the mind and easily retained; but when a knowledge of the value of remedies is required for practical purposes, to effect a desired object in the treatment of disease, then a classification based upon some physiological grounds will be found to be the more feasible.

In the following classification, the author has been guided by a desire to make it one of practical utility rather than of scientific interest; and he feels assured that in the present imperfect state of our knowledge of the action of medicines upon the animal economy, he shall best effect this by referring his arrangement to the organs and structures of the body which are influenced by the drugs rather than to the character of the action thereby exercised.

It has been the object of the author to retain such grouping of medicines as experience has long confirmed and ratified, and to avoid such subtleties of division as serve only to perplex the mind and lead to no useful results.

Classification of medicines

• Division 1. Internal remedies; medicines which are administered for their effects upon the system both before and after absorption into the blood.
  • Class 1.1: Agents acting on the blood
    
    • Order 1.1.1. Blood Tonics, Analeptic Tonics, Blood Restoratives.
    • Order 1.1.2. Alkaline Remedies
    • Order 1.1.3. Acids and Astringents
    • Order 1.1.4. Refrigerants
    • Order 1.1.5. Alteratives.
  • Class 1.2: Medicines whose principal effects are seen upon the nervous system
    • Subclass 1.2.1: Acting on the brain: Exhilarants, narcotics, anaesthetics.
    • Subclass 1.2.2: Acting on the spinal cord
    • Subclass 1.2.3: Acting on portions of the nervous system
  • Class 1.3: Medicines acting chiefly on the heart and circulating system; probably often through the sympathetic system of nerves
    • Order 1.3.1. Vascular Stimulants
    • Order 1.3.2. Vascular Sedatives
    • Order 1.3.3. Vascular Tonics
  • Class 1.4: Agents Acting on Special Organs
    • Subclass 1.4.1. Agents acting on parts of the alimentary canal
      • Order 1.4.1.1. Sialogogue
      • Order 1.4.1.2. Emetics
      • Order 1.4.1.3. Purgatives and Laxatives.
        • Group 1. Laxatives
        • Group 2. Simple purgatives
        • Group 3. Drastic purgatives
        • Group 4. Hydragogue purgatives
        • Group 5. Saline purgatives
        • Group 6. Cholagogue purgatives
      • Order 1.4.1.4. Anthelmintics
      • Order 1.4.1.5. Stomachic tonics
      • Order 1.4.1.6. Stomachic stimulants or carminatives.
      • Order 1.4.1.7. Stomachic sedative
    • Subclass 1.4.2. Medicines affecting the respiratory organs and passages
    • Order 1.4.2.1. Errhine
    • Order 1.4.1.2. Expectorants (pulmonary stimulants)
    • Order 1.4.1.3. Pulmonary sedatives.
    • Subclass 1.4.3. Medicines acting on the function of the skin
      • Order 1.4.3.1. Sudorifics, diaphoretics
    • Subclass 1.4.4. Medicines affecting the function of the kidneys and urinary organs.
      • Order 1.4.4.1. Diuretics
      • Order 1.4.4.2. Lithonotriptics
      • Order 1.4.4.3. Medicines influencine mucous membranes of the urinary tract.
    • Subclass 1.4.5. Medicines whose action is on the generative organs.
      • Order 1.4.5.1. Emmenagogues and Ecbolics.
      • Order 1.4.5.2. Aphrodisiacs.
      • Order 1.4.5.3. Anaphrodisiacs.
    • Subclass 1.4.6. Medicines which act on the eyes
• Division 2.  External remedies; or medicines which act locally, and are not yet employed to affect the constitution.
  • Order 2.1. Irritants
    • Group 2.1.1. Rubifacients
    • Group 2.1.2. Epispastics or blistering agents
    • Group 2.1.3. Pustulants.
  • Order 2.2. External sedatives
  • Order 2.3. Emollients and demulcents.
  • Order 2.4. Astringents and styptics.
  • Order 2.5. Caustics and escharotics
• Division 3. Chemical agents used for other than their medicinal properties
  • Order 3.1. Antidotes
  • Order 3.2. Disinfectants and Antiseptics
    

DIVISION 1

CLASS 1.1. MEDICINES WHOSE PRIMARY ACTION IS UPON THE BLOOD, ALTERING ITS CHARACTER

Order 1.1.1. BLOOD TONICS, ANALEPTIC TONICS, BLOOD RESTORATIVES. Medicines which possess the power of improving the quality of blood, by the restoration of the principles in which it is deficient.

Appropriate alteration of the diet to suit individual cases - as fresh fruit and vegetables.

Adjuvants to blood tonics.  Fresh air, light, exercise.

Effects of Blood Tonics

The effects produced by the different blood tonics are necessarily of a very diverse nature.  If the blood is deficient in any element or proximate constituent, the exhibition of medicine, or food containing such deficient substance, has the effect of restoring the fluid to a healthy condition.

In the lower animals, when living in a state of nature, it is probable that, so long as they are able to procure food, such a state of blood rarely occurs; for their diet contains all that is essential. If the animal be carnivorous, then he eats all the parts of his prey, including the blood; if herbivorous, the vegetable substances contain all that is necessary in his food.

Man, however, distinguished by being an animal which cooks his food, in doing so, sometimes deprives his diet of some of the essential elements, and hence disease may from this cause be engendered.  The most frequent morbid conditions which ensue from deficiency in diet, as also from other causes, are: anaemia, or bloodlessness, caused by a deficiency of red corpuscles of the blood; wasting or imperfect flesh-making, and true scorbutus or scurvy.

Therapeutic applications of Blood Tonics

The use of blood tonics is indicated in the above-named conditions.  If anaemia be present, then the salts of iron, the peculiar properties and value of which will be found under the respective heads, should be given.  The value of the manganese salts in such cases is questionable.  If there is wasting of the body from different causes, then cod-liver oil is valuable, or some fatty or oily matter should be added to the food; and lastly, if there is a scorbutic condition, then fresh vegetables and fruits, and certain salines contained in them, prove almost invariably curative.

Order 1.1.2. ALKALINE OR ANTACID MEDICINES. Agents which increase the normal alkalinity of the blood, and through it, either reduce the acidity, or render alkaline the secretions which are acid in health, or increase the alkalinity of such as are normally alkaline.

Effects of Alkaline or Antacid Remedies.

It will be seen that a subdivision of these medicines is made into direct and remote antacids.  The direct antacids are alkaline in their reaction, will turn reddened litmus paper blue, and hence when they come in contact with acid in the alimentary canal they neutralize it at once; after absorption into the blood they probably increase the alkalinity of this fluid, and certainly, with the exception of the salts of ammonia, cause the alkalinity of the secretions, especially of the urine.  The remote antacids differ from the first subdivision in possessing no alkaline reaction; in fact one, the cream of tartar, or acid tartrate of potash, has a strong acid reaction; hence they cannot be used if the neutralization of acid in the stomach or intestines is desired.  Free ammonia and its carbonate have the power of neutralizing acid in the alimentary canal, but do not affect the urine; their effect on the blood have not been determined.  Independent of their alkaline or antacid powers, each group of these remedies has some special effects on different organs; thus, potash salts act more especially on the kidneys, soda salts upon the liver, lime salts tend to cause constipation, and magnesia salts a purgative effect.  Ammonia salts appear to influence the skin and pulmonary mucous membranes; whether they diminish the alkalinity of the secretions of these parts has not been clinically demonstrated.  The acids of the salts of the fixed alkalies and alkaline earths are decomposed in the system, and the bases appear in the urine in the form of carbonates.

Therapeutic applications of Antacid or Alkaline Remedies

1. To neutralize acidity in the stomach and intestines, and hence relieve heartburn and other symptoms induced by an over acid state of the alimentary canal.
2. To augment the alkalinity of the blood, which is altered in many diseases, as in febrile states, rheumatism, gout, albuminuria, &etc.
3. To alter the secretions from the blood, more especially the urine (see Lithontriptics), and to influence the secreting organs and the mucous membranes of many parts.

From what has been stated under the head of the Effects of Alkaline Medicines, a proper selection of them can readily be made in different diseases.

Order 1.1.3. ACIDS AND ASTRINGENTS  Acid and astringent medicines have been grouped together, because it is probable that all the acids, vegetable and mineral, are more or less astringent in their action, although there are other drugs not acid in reaction which still are powerfully astringent; hence the acids form only one group of these latter remedies.  Astringents are substances which produce some alteration in the composition and character of the blood, increasing its disposition to coagulate, and probably causing at the same time contraction of the blood-vessels and a diminution of the secretions from the different organs and secreting surfaces throughout the body.

Effects of Astringent Medicines.

The blood is always alkaline in reaction, from the presence of the alkaline phosphate of soda and some alkaline carbonates.  An excess of alkalinity appears to give it greater fluidity or less coagulating power, and on the contrary, a diminished alkalinity increases its adhesive quality and property of forming firm clots: it seems probable that the mineral acids, when absorbed into the blood, effect this object and hence are astringents; most of them possess the property of forming insoluble compounds with albumen.  The vegetable acids possess similar properties, but in very different degree; the most powerful are the tannic, gallic, and other allied acids, as catechuic, and many vegetable substances containing these, as catechu, kino, &c.; the same remarks apply to some of the metallic astringents.

Turpentine, creasote and carbolic acid, exert much of their influence by causing contraction of the blood vessels. Some astringents appear to act through the central nervous system, as opium, ergot of rye, and probably the salts of lead.

Therapeutic applications of Astringents.

1. To arrest haemorrhages from any organ or surface.  This is effected by altering the character of the blood, and causing contraction of the blood-vessels supplying the bleeding parts.
2. To restrain excessive discharges from mucous membranes, an effect also produced by the changes in the blood itself and the blood-vessels.
3. To diminish an abnormal amount of the secretion from any organ, as of the skin in cases of excessive sweating; of the urine in excessive diuresis/

Order 1.1.4. REFRIGERANTS  The name refrigerant is given to a medicine which is supposed to have the power of cooling the body when in disease, and hence allaying febrile disturbance.

Effects of Refrigerants.

It will be observed that these medicines differ very much among themselves, although most of them belong to the group of acid and astringent remedies; their action in lowering the temperature of the body has never been clinically established, and is doubtful; still it is a fact that, when a patient is feverish, the acids and the juices of acidulous fruits are very grateful in relieving thirst.

Therapeutic applications of Refrigerants.

To allay thirst in febrile disturbance.

Order 1.1.5. ALTERATIVES  The blood tonics and alkaline remedies, as likewise those which are acid and astringent, may all be said to be alterative in character; and their action is, more or less, understood; there are, however, remedies constantly employed in the treatment of disease which are termed alteratives; medicines which produce certain, at present, ill-understood changes throughout the system, but whose influence is frequently valuable.  Such alteratives may be conveniently subdivided into groups.

Effects of Alteratives

The effects of the alteratives in the above groups are of so varying a character, that it is almost impossible to define them, unless the detailed operation of all the medicines be given; such effects will be found severally described under each separate substance.  They all produce some alteration in the state of the blood, and hence upon the system at large.  In some, however, the influence is most marked upon the glandular system, in others upon the serous membranes, in others upon the mucous membranes, and again, in a fourth class upon the cutaneous tissue.

Under the influence of these alteratives peculiar morbid systemic affections become alleviated or removed, as is observed in the exhibition of mercurials and iodides in secondary syphilis and scrofula; also conditions of the body giving rise to cutaneous eruptions.  Many of the so-called alteratives appear to exert an influence in chronic inflammatory states of the system, and to have the power of removing the morbid products which have occurred during such action.

Therapeutic applications of Alteratives.

From what has been stated in former parts of this work, the indications for the administration of these remedies will be readily arrived at, and need not be further alluded to in this place.

CLASS 1.2. MEDICINES WHOSE PRINCIPAL EFFECTS ARE UPON THE NERVOUS SYSTEM.

SUBCLASS 1.2.1. Medicines acting especially upon the brain proper; but probably also upon other portions of the central nervous system.

Order 1.2.1.1. EXHILARANTS  Exhilarants are medicines whose primary effect is to cause an exaltation of the spirits, and through this influence on the brain, a general excitement or augmentation of the functions of the whole body: if taken in large quantities, many of them produce intoxication, and are called therefore inebriants.

Effects of Exhilarants.

These are sufficiently indicated in the definition ; they stimulate the vascular system through the influence of the nervous.  Their effects are transient.

Therapeutic applications of Exhilarants.

These remedies are given in low conditions of the nervous system, and in cases in which there is the necessity to stimulate for a time the heart and circulating system.

Order 1.2.1.2. NARCOTICS, ANODYNES, AND SOPORIFICS. Medicines which act upon the brain, alleviating pain (anodynes), and some causing direct sleep (soporifics).

Soporifics and anodynes

Opium.
Salts of morphia.
Indian hemp.
Hops (?)
Lettuce (?)
Bromide of potassium.
Bromide of Ammonium.

Anodyne and Antispasmodic

Belladonna.
Atropia.
Stramonium.
Hyoscyamus.

Also:

Aconite.
Aconitia.
Digitalis.
Digitalinum.

Effects of Narcotics.

All the remedies in the above list, except those to which queries are attached, and probably the bromides, produce stupor if the dose be increased beyond a certain point, and are hence called narcotics; still the different members differ essentially from one another in their action.  Certain of them, soporifics, produce direct sleep; this is the case with opium and morphia salts: bromide of potassium and Indian hemp will also cause drowsiness.

Others, which may be termed anodynes, allay pain; but in large doses there is delirium rather than sleep induced.  The action of opium differs considerably from that of belladonna: opium causes contraction of the pupil; belladonna dilates it.  Indian hemp neither contracts nor dilates the pupil.  Under the influence of opium the brain probably becomes congested; whereas under belladonna it becomes deficient in blood from the contraction of the arteries of the organ.

Belladonna, stramonium, and henbane, appear to act on the sympathetic system of nerves.

Sleeplessness may arise from different states of the brain, and therefore some of these remedies may prove useful at one time, others at another.

Aconite produces a numbness and loss of sensation in the extremities, and when topically applied it produces local anaesthesia.  Digitalis sometimes causes sleep from its influence on circulation.

Therapeutic applications of Narcotics.

Narcotics are used in medicine for different purposes.

1.  To procure sleep (soporifics).
2.  To allay pain and diminish spasm (anodynes).

Order 1.2.1.3. ANAESTHETICS. Substances which when inhaled in the form of vapour possess the property of destroying consciousness, and at the same time causing insensibility to pain: they are therefore soporifics and anodynes, but their effect is more immediate and much less persistent than that of ordinary narcotics.

Chloroform
Ether
Tetrachloride of carbon
Bichloride of methylene
Protoxide of nitrogen (nitrous oxide

Effects of Anaesthetics.

These have been sufficiently detailed under the respective heads of the above anaesthetic agents.

Therapeutic applications of Anaesthetics.

1.  To alleviate pain and spasm.
2.  To produce unconsciousness and insensibility to pain during surgical operations and parturition.
3.  To procure sleep and diminish violence in delirium tremens and some other forms of cerebral disturbance.
4.  To cause relaxation of the muscular system, in order to facilitate the reduction of dislocations and of hernia.

SUBCLASS 1.2.2.  Medicines acting especially upon the spinal cord.

Order 1.2.2.1. SPINAL STIMULANTS  Medicines which increase the function of the spinal cord.

Effects of Spinal Stimulants.

The action of strychnia, detailed under the therapeutics of that remedy, affords a typical illustration of the physiological effects produced by these bodies.  The specific action of many of the substances in the list upon the spinal cord is somewhat doubtful; their other influences are often more apparent.  The spinal properties of opium are seen best in the lower animals, where the cerebral hemispheres are less developed.

Therapeutic applications of Spinal Stimulants.

The use of these remedies is indicated:

1.  In cases of paraplegia, when there is no evidence of inflammatory action.
2.  In cases of local paralysis.
3.  In some forms of hemiplegia.
4.  In cases of functional debility of the cord.

Order 1.2.2.2. SPINAL SEDATIVES   Medicines which diminish the function of the spinal cord.

Effects of Spinal Sedatives.

The action of conium and its alkaloid is the reverse of that of strychnia; it causes paralysis of the extremities, the function of the brain remaining intact.  The bromides also appear to influence the function of the nervous system.  Hydrocyanic acid acts on the whole nervous system, so that its special influence on the spinal cord cannot be readily shown.

Therapeutic applications of Spinal Sedatives.

Spinal sedatives are used in the following cases:

1.  In irritated conditions of the spinal cord; as in cases of paraplegia accompanied with inflammatory action.
2.  In spasmodic affections, as nervous forms of cough and pertussis.
3.  In affections in which there is over-excitement of the generative organs.

SUBCLASS 1.2.3. Medicines acting upon some portions of the nervous centres, and on the ganglionic system.

Order 1.2.3.1. ANTISPASMODICS. Antispasmodics are medicines which possess the property of allaying spasm, probably by giving tone to the spinal cord.

Effects of Antispasmodics.

The direct antispasmodics appear to give tone to the spinal cord and other parts of the nervous system, and through these to the muscular system, and hence they diminish the susceptibility to spasm; their typical action is seen in that of assafoetida.

The indirect antispasmodics in the table act in very different ways; some by their direct sedative influence upon the spinal cord, as conium; some by bracing up the whole nervous system, as the zinc salts and other nervine tonics; and some by their influence upon the brain, as the various narcotic remedies.

Therapeutic applications of Antispasmodics.

The use of the direct antispasmodics is indicated:

1.  In spasm depending on hysteria, and other weakened conditions of the nervous system.
2.  In other forms of spasm; in which they should be combined with remedies which remove the cause of the spasm.

Order 1.2.3.2.  NERVINE TONICS AND ANTIPERIODICS   Nervine tonics are remedies which give tone to the nervous system in general, and some (antiperiodics) possess the power of arresting intermittent forms of diseases.

Effects of Tonics and Antiperiodics.

Although all the antiperiodics in the above list are tonics to the nervous system, yet there are many substances therein placed which do not possess antiperiodic powers, and hence they must be subdivided into groups, for practical purposes.  The way in which these different tonics act, and the parts upon which the action is exerted, are at present not understood.  It will be seen that queries have been placed to several of the medicines in the list, many substances having been proposed as antiperiodics of which experience has not confirmed the value.

Therapeutic applications of Nervine Tonics and Antiperiodics.

The antiperiodic tonics are administered in the following cases:

In all forms of intermittent fevers.
In intermittent forms of neuralgia.

The nervine tonics in spasmodic affections of the nervous system, as chorea, epilepsy, hysteria, and other forms of nervous diseases, also in cases of nervous debility.

CLASS 1.3. MEDICINES ACTING CHIEFLY ON THE HEART AND CIRCULATING SYSTEM, PROBABLY OFTEN THROUGH THE SYMPATHETIC SYSTEM OF NERVES

Order 1.3.1. VASCULAR STIMULANTS

Effects of Vascular Stimulants.

There are certain drugs which act more especially as stimulants to the heart and large vessels, others on the minute arteries and capillary system, and in practice it is important to separate them; thus, if it is desired to rouse the heart quickly to more powerful action, ammonia and the carbonate of ammonia will often effect the object, whereas the salts of ammonia, in which the alkali is combined with a vegetable acid, as the acetic or citrate, will be powerless, although the action of these salts may prove of much value in increasing the capillary circulation; the vascular stimulants which act in these different ways are indicated in the list.

Therapeutic applications of Vascular Stimulants.

The use of the above remedies which act especially on the heart is indicated in cases in which the function of this organ is very languid; this condition may occur from many causes, either temporarily from a lowering of the nervous supply of the heart, or more permanently in cases where the walls of the organ have become weakened; in the latter the stimulants should either be combined with vascular tonics, or the use of the latter should be soon substituted for the former.

Those vascular stimulants which act on the small vessels and capillary circulation are indicated in chronic inflammatory affections in which the circulation of the diseased parts is sluggish; and also to aid the absorption of matters deposited during the more acute inflammatory stages.  Many of these remedies augment the function of various special organs.

Order 1.3.2. VASCULAR SEDATIVES. Vascular sedatives are medicines which possess the power of depressing the action of the heart or other portions of the circulating system.

Effects of Vascular Sedatives.

As in the case of vascular stimulants, so with vascular sedatives; some act more especially on the heart itself, others on the smaller vessels; and the division into the two groups is of real therapeutic importance.  Those acting principally on the heart often cause intermission of the pulse, as digitalis, colchicum and aconite.

Therapeutic applications of Vascular Sedatives

When the heart is turbulent in its action, then the sedative remedies which act upon this organ are indicated; the medicine most frequently resorted to is digitalis; it seems probable that this drug in reality stimulates the heart through its nerves, but nevertheless the effect is sedative, the organ becomes quieter, and the circulation more perfect; it must be remembered that a turbulent cardiac condition is often combined with a very imperfect flow of blood through its cavities.  The other remedies, as green hellebore, aconite, and colchicum, are sometimes used as direct cardiac sedatives.  The preparations of antimony appear only to depress the heart's action along with that of the general circulating system, and they are employed, as are also green hellebore and other sedatives, to subdue vascular action in inflammations of various organs.  It is questionable whether hydrocyanic acid acts on the vascular system, except in an indirect manner; it is most useful as a cardiac sedative when the over-action is dependent on dyspepsia.  Colchicum has certainly a very notable, almost specific power, over gouty inflammation.  Ipecacuanha, in large doses, has considerable power in lowering the circulation, and both it and acetate of lead may be used in many forms of haemorrhages with much advantage.  Ergot may also be employed especially in menorrhagia.

Order 1.3.3. VASCULAR TONICS. Vascular tonics are medicines which give tone or strength to the heart and other parts of the circulating system when weakened by disease.

DIVISION CLASS 1.4  AGENTS ACTING ON SPECIAL ORGANS

SUBCLASS 1.4.1. Medicines which act especially on the different portions of the alimentary canal.

Order 1.4.1.1. SIALAGOGUES. Sialagogues are medicines which have the property of exciting the flow of saliva and buccal mucus.

Effects of Sialagogues

Some sialagogues produce their effects by their topical action; some by their influence after absorption into the system, and some possess both these properties, more especially tobacco.  When iodide of potassium is administered, a peculiar taste is frequently detected in the mouth, and sometimes a marked increase of mucus is observed; but many of the recorded cases of salivation and ptyalism are instances of the power of iodine in bringing mercury which had been previously taken by the patient back into the blood, and causing it to reproduce the ordinary symptoms of this metal.

Therapeutic applications of Sialagogues.

The objects to be gained by the use of sialagogues is the relief of dryness of the mouth which is sometimes present in disease, and occasionally the production of a derivative effect and the alleviation of some neighbouring morbid action.  Sialagogue medicines are seldom used medicinally for their action as such.

Order 1.4.1.2. EMETICS. Emetics are medicines which cause vomiting, by producing an inverted action of the stomach and oesophagus and the emptying of the stomach of any contents which may be present.

Effects of Emetics.

The removal of the contents of the stomach by the act of vomiting is usually the principal effect sought for in the administration of emetics, but there are others which attend upon this act, sometimes preceding and following it, and the division of the remedies in this group depends upon the amount of the accompanying phenomena.  The most constant of these are nausea, an increased secretion of mucus from the stomach and gullet, frequently a flow of bile from the gall-bladder into the duodenum, and its partial regurgitation into the stomach; also an increased flow of mucus from the bronchial tubes: emetics are therefore to some extent cholagogues and expectorants.  Besides this, the act of vomiting is attended with more or less depression of the nervous system, diminution of nervous energy and of muscular contractility; there is usually an increased action of the skin, sweating or diaphoresis.  Direct emetics produce very little of the above phenomena.

Therapeutic applications of Emetics.

The more direct emetics are especially indicated when the emptying of the stomach or the mere act of vomiting is alone desired; as in cases of poisoning to remove the peccant matters: in such cases mustard, from the rapidity of its action, and the facility with which it can be procured, is peculiarly adapted.  These emetics are also useful in certain cases in which very indigestible food has been taken, and discomfort thereby produced.  Sometimes in disease the act of vomiting is useful for its mechanical effects, as in some cases of phthisis, bronchitis, and croup.  Sulphate of copper is said to be more powerful than sulphate of zinc, but its administration has disadvantages, for, if absorbed, the copper may cause unpleasant symptoms; it is seldom used, and only in severe cases of opium poisoning when it is very difficult to cause vomiting.  Carbonate of ammonia in large doses is indicated when a stimulant effect upon the heart is required as well as the mechanical effect, as in cases of asthenic bronchitis.  The indirect emetics are used in inflammatory diseases, especially of the chest.

Order 1.4.1.3. PURGATIVES OR CATHARTICS. Purgatives are medicines which cause an increased action upon the bowels i.e. an unloading of the large and small intestines, with more or less alteration in the character of the evacuations.

Adjuvants to Purgatives.

a. By giving tone or contractile power to the intestines:  Nux vomica and strychnia, sulphate of iron.
b. By causing more equal contraction and diminishing spasm:  aromatic and other volatile oils; henbane, stramonium, and belladonna.
c. By increasing the mucous secretion from the canal and by diminishing spasm: Ipecacuanha and antimonials, in small doses.
d. Enemata, cold, & etc. to abdomen.

Effects of Purgatives or Cathartics.

As above stated in the definition, all purgatives cause an increase in the peristaltic action, or of the normal vermicular movement of the intestinal tube; but the various medicines in this class act so differently in other respects, that they are capable of being subdivided with advantage into groups for practical purposes: all purgatives have also a tendency to diminish the consistency of the faecal evacuations, for mere increase of the rapidity of transit through the canal effects this, by preventing the complete absorption of liquid in the large intestines

1.  The term laxatives is given to purgatives which appear to effect little more than an increased peristaltic movement, and a slight softening of the faeces; some act more powerfully than others, and in the above table they are arranged in order, the mildest being placed at the top of the list.

2.  Simple Purgatives are medicines the peristaltic action of which is greater than that of laxatives, but the other effects of the drugs in the subsequent groups are produced in a slight degree; that is, there is no great increase in the secretion of the mucous membrane and its various small glands, nor in the exhalation of serosity from the membrane.  If a more complete knowledge could be obtained of the minute action of different purgative remedies, they would in all probability be capable of subdivision into still smaller groups, for each has doubtless some peculiarity in its action separating it from the rest, although such peculiarity may not be capable of being clearly, defined at the present time; some, for example, act more on the upper part of the small intestines, some on the lower portion, others again on the large bowels.  Some purgatives augment the flow of fluid from the general surfaces of the intestinal canal, some increase in a great degree the peristaltic movement, and lastly, some influence the large secreting organs in connection with the intestinal canal, as the liver and pancreas.  Among the simple purgatives these differences are well seen; aloes, for example, acts notably upon the large bowel, and scarcely increases the fluid secretion from it, whereas jalap causes a greater flow; senna produces much contraction of the gut and griping. In the exhibition of simple purgatives, little more than the emptying of the canal is looked for by the therapeutist.

3. Drastic Purgatives.  There is no well marked line to be drawn between simple and drastic purgatives; they appear only to differ in the degree of their action.  In the administration of drastic purgatives the unloading of the bowels is but one object; a greater one looked for in the derivative effect produced by the irritation of a large mucous surface, and also from a rather free elimination of fluid and of glandular secretions.

4.  Hydragogue Purgatives possess the peculiarity of causing a very large secretion of fluid from the mucous membrane of the bowels.  All drastic purgatives are hydragogue to some extent, but in the case of elaterium and cream of tartar, the amount of fluid is in excess of the violence of the operation in other respects.  Cream of tartar will sometimes, if given alone, fail to produce a purgative effect, and yet its hydragogue action is fully produced; that is, it causes a copious flow into the intestinal tube, which may be again absorbed if the medicine is not combined with some other drug to cause its elimination.  Many authors place gamboge in this group.  The effect produced by hydragogues, beyond the ordinary purgative action, is the relief or partial emptying of the veins of the portal system, and hence of the whole circulation, together with the derivative action as in the case of ordinary drastic purgatives.

5.  Saline Purgatives.  The drugs in this group differ from those in the last in the degree of watery discharge which they produce, and in their action not being drastic in character: cream of tartar might fairly be included among them, and regarded as a link between the saline and hydragogue purgatives.  Saline purgatives produce a similar effect to the hydragogue purgatives, but much slighter, together with the ordinary action of other purgatives; unless taken in a very diluted state and in large quantities, as in the form of Pullna and Freidrick-hall bitter water, they are best given in combination with other aperients.

6.  Cholagogue Purgatives.  Certain purgatives appear to act upon the large secreting glands connected with the alimentary canal, especially the liver, possibly the pancreas also, and cause a flow of bile into the intestines; to these the name cholagogue is given.

It is questionable if these drugs have any specific effect upon the bile-secreting functions of the liver; and it is probable that many of them act simply by causing an emptying of the gallbladder, and it is a fact that retention of bile within the ducts and gall-bladder is a very common occurrence in civilised society.  It must be remembered that almost all purgatives produce more or less cholagogue effect, the saline less than the rest.  It will be observed that some medicines are placed in this group with reservation, as taraxacum and colchicum; those regarded as most efficient are the preparations of mercury and, lately, the resin of podophyllum.

Adjuncts to Purgatives.  The purgative action of many drugs may be much aided by combination with others which do not of themselves possess any marked power of acting upon the alimentary canal; illustrations of such combinations have been already given; the medicines most frequently combined with purgatives are seen in the above table, and the peculiarities of their action sufficiently indicated.

Purgative Agents.  The use of enemata of any liquid.  The application of cold to the abdomen, as cold affusion, compresses of wet cloths and etc.

Therapeutic applications of Purgatives.

The different kinds of purgatives are employed for various purposes:  1. To unload the bowels, if not sufficiently acted upon.  2.  To remove any irritating matters.  3.  To cause an increased elimination of the secretions from the liver and pancreas, as also from the numerous glands of the mucous membrane of the alimentary canal.  4.  To unload the veins of the canal, if full, by causing an increased watery secretion from the membrane; by this means often removing congestion of internal organs, as the kidneys, and increasing their function.  5.  To produce a derivative effect or counter-irritation; that is, by causing an irritation and increased secretion from a large mucous surface, and thus relieving distant parts, as the head, &etc.

Order 1.4.1.4. ANTHELMINTICS Substances which have the power of destroying the life of entozoa in the alimentary canal.

Effects of Anthelmintics.

The three entozoa commonly found in the alimentary canal of the human subject are, the tape worm taenia solium), the round worm ascaris lumbricoides), and the thread worm (ascaris vermicularis); the first occupying the small intestines and extending upwards and downwards; the second, chiefly the caecum and ascending colon; the third, the rectum and descending colon.  The true vermicides or direct anthelmintics, when they come into contact with, the entozoa, either kill them or produce such an effect upon them that they are easily dislodged.  Some of them, as male fern, kousso, and kamala, appear to act more effectually upon the tape worm; worm seed, and its active principle, santoninum, upon the round worm.  Some of the direct anthelmintics are purgative also in their action, as kamala; but the use of others requires to be followed by that of a cathartic.  The worm-preventives are medicines which give tone to the intestinal membrane, and prevent the over-secretion of mucus, which forms a nidus in which the entozoa increase and lodge.  Quassia and nux vomica probably are vermicides as well as intestinal tonics.

Therapeutic applications of Anthelmintics.

Anthelmintics are employed for the following purposes:

1.  The direct, or vermicides, to destroy any worms present in the alimentary canal.
2. The indirect, or vermifuges, to expel any worms, living or dead.
3.  The worm-preventives are administered after the expulsion of worms, to fortify the body and prevent their return.  The direct anthelmintics should be taken when the patient has fasted for many hours; it is often advantageous to give a cathartic some hours before and also three or four hours after; the object of these precautions being to enable the drug to come into close contact with the entozoa, and also to cause their expulsion as soon as they are injured or killed.  Thread-worms are best treated by the exhibition of anthelmintics in the form of enemata, as they inhabit the lower part of the canal.

Order 1.4.1.5.

STOMACHIC TONICS. Stomachic tonics, or stomachics, are medicines which act directly upon the stomach, improve appetite, and aid the digestive function.

Effects of Stomachic Tonics.

In the above list it will be seen that the included drugs are separated into several groups, and such subdivision is not without practical value.  Some stomachics appear to act simply by improving the mucous membrane, others by acting on the nervous system and giving tone to the stomach; a third group, by adding to the digestive principles; and a fourth, by altering the state of the lower portion of the intestinal canal and thus relieving any morbid condition of the stomach itself.

Therapeutic applications of Stomachic Tonics.

In cases of simple debility of the mucous membrane of the stomach, caused by long-continued dyspepsia, and by the free use of alcohol, the medicines in the first group are useful. In atonic indigestion from debility of the nervous system and anaemia, the members of the second group are indicated, iron salts if anaemia is present. In simple atonic dyspepsia from old age and other causes, pepsin is useful.  When atonic indigestion is combined with a torpid state of bowels and liver, taraxacum, aloetics, and rhubarb, alone or combined with other stomachics, prove of much value.

Order 1.4.1.6. STOMACHIC STIMULANTS OR CARMINATIVES. Carminatives are medicines which act as stimulants to the stomach, causing expulsion of flatulence, also allaying pain and spasm of the intestines.

Effects of Carminatives.

It will be observed that the majority of the substances in the above list contain a volatile oil, which is aromatic in nature; some are used as ordinary condiments; they act as stimulants to the mucous membrane of the stomach and intestines, relieve spasm of the muscular coat, and hence give a greater regularity to the ordinary vermicular action of the canal.

Therapeutic applications of Carminatives.

These remedies may be used: 1.  In cases of distension and colicky pains of the stomach or intestines from flatulence: they may be combined with other indicated medicines.  2.  As adjuncts to purgatives, the action of which they often assist, and at the same time they diminish their griping tendency. 3.  Some of these substances are used in order to assist the digestive process, in cases of atonic dyspepsia; more especially capsicum, mustard, ginger, pepper, and horseradish.

Order 1.4.1.7. STOMACHIC SEDATIVES. Medicines which allay irritation of the stomach and upper part of the intestinal canal, by producing a direct sedative action upon the mucous membrane.

Effects of Stomachic Sedatives.

The remedies in this list differ widely in the character of their action, yet under certain circumstances all of them may be employed to allay pain: some appear to act by their direct sedative influence on the nerves of the mucous membrane, others by their influence on more central parts of the nervous system: in the first class are the bismuth and silver salts, the alkaline preparations, and prussic acid; in the second, belladonna, stramonium, henbane, and opium, more especially the latter.

Therapeutic applications of Stomachic Sedatives.

The use of stomachic sedatives is indicated in:  1.  Painful affections of the stomach and duodenum, as in gastrodynia, enterodynia: hydrocyanic acid and belladonna are most useful in these cases.  2.  In conditions of the stomach accompanied with pyrosis or water brash: in these cases bismuth salts are peculiarly useful.  3.  In vomiting: the selection of the remedy must depend on the condition of the stomach giving rise to this symptom: when there is much increased vascular action and a sub-inflammatory state, prussic acid and alkalies may be taken; when the affection is chronic, creasote and carbolic acid: in vomiting from pregnancy, cerium salts are stated to be useful.

SUBCLASS 1.4.2 Medicines affecting the respiratory organs and passages.

Order 1.4.2.1. ERRHINES OR STERNUTATORIES  Errhines are medicinal substances which possess the property of exciting a secretion of mucus from the nasal mucous membrane, and this is very frequently accompanied with sneezing.

Effects of Errhines.

The effects of errhines are almost sufficiently described in the definition; it may, however, be remarked that some of these substances merely cause an irritant effect upon the surface to which they are applied, but others, especially strong tobacco, produce a secondary influence upon the system, from the subsequent absorption of the drug.

Therapeutic applications of Errhines.

In great dryness of the mucous membrane of the nasal passages.  In some forms of headache, which are relieved by these remedies, partly on account of the increased secretion of mucus and the consequent unloading of the blood-vessels of the membrane, and partly from the derivative effect which is caused by the irritation of the membrane, and also by the act of sneezing.

Order 1.4.2.2. EXPECTORANTS  Expectorants are medicinal substances which affect the mucous membrane of the pulmonary passages, causing an increased secretion of mucus, and often an altered state of the mucus itself.

Effects of Expectorants.

The remedies in the above list appear to be of very diverse kinds, and groups may be usefully formed for practical purposes.  In the first division, the drugs are more or less stimulant upon the vascular system; in the second, sedative in their action; still, under certain conditions, each produces an augmentation of the mucous secretion from the bronchial tubes.  Watery vapour relaxes the membrane; the vapours of chlorine and ammonia act as direct stimulants.

Therapeutic applications of Expectorants.

The remedies of the first group are applicable in chronic forms of bronchitis unattended with febrile disturbance; they often increase cough and produce discomfort if fever is present.  The drugs in the second group are distinctly sedative upon the vascular system, and are more adapted for the treatment of the early stages of bronchitic inflammation, and when febrile disturbance is present.  The vapour of water is useful in many cases, and is most conveniently applied by allowing steam to enter the patient's apartment.  Chlorine and ammonia vapour used in the form of inhalation can only be employed in very chronic forms of disease, as likewise the vapour of creasote and carbolic acid.

Order 1.4.2.3. PULMONARY SEDATIVES  Pulmonary sedatives are substances which produce a direct sedative effect upon the respiratory organs, frequently diminishing the secretion from the mucous membrane of the bronchial tubes.

Effects of Pulmonary Sedatives.

Little more can be stated with regard to the action of these remedies than what is contained in the definition; the primary action of the different members may be of diverse character, but the effects on the pulmonary organs very similar.  Conium, for example, acts as a direct sedative upon the spinal cord; acetate of lead as a direct sedative to the vascular system.

Therapeutic applications of Pulmonary Sedatives.

When cough is of an irritative or spasmodic character, then hydrocyanic acid, conium, belladonna, and stramonium are useful; also, in many cases, opium or morphia.  When the secretion from the mucous membrane is excessive, opium, morphia, and acetate of lead are indicated.  These sedatives may frequently be advantageously combined with expectorants of a sedative character, as antimony and ipecacuanha.  When used in the form of inhalation, or when smoked, these remedies are usefully employed in diminishing cough and spasmodic difficulty of breathing, and usually a much smaller amount of the drug is required under these circumstances, as the effect is first and especially produced upon the affected parts.

SUBCLASS 1.4.3. Medicines acting on the function of the skin.

Order 1.4.3.1. SUDORIFICS OR DIAPHORETICS  Sudorifics or diaphoretics are medicines or medicinal agents which cause an increase of the function of the skin.

Effects of Sudorifics.

The function of the skin may be promoted by two apparently opposite kinds of medicines, namely, those which stimulate the vascular system and those which act as sedatives to the same; and hence a convenient subdivision may be usefully adopted into stimulant and sedative sudorifics.

The ammonia salts, with a vegetable acid, are probably decomposed, and the ammonia partly, at least, eliminated by the skin, thus increasing its function.  The volatile oils and resins contained in the stimulating vegetable sudorifics appear to increase the cutaneous capillary circulation, and hence the secreting function is necessarily augmented.  Opium and morphia salts in small doses are certainly diaphoretic in their action, and probably stimulant in their effects.  The first are especially indicated in cases in which the circulation is sluggish, whereas the sedative sudorifics are adopted to promote sweating in patients whose skin is hot, and in whom febrile disturbance is present.

The therapeutic agents classed under the head of sudorific aids are usefully combined with both kinds of diaphoretics.

It is probable that the skin has a double function; in the first place it eliminates water from the system by evaporation, and secondly it secretes from the blood certain organic and inorganic matters, in the same way as the kidneys and liver; it is also probable that certain sudorifics augment the one function especially, certain the other.

Therapeutic applications of Sudorifics.

Sudorific remedies are called for the following purposes:

1.  To restore the action of the skin in cases in which its function has been checked by cold or other causes.

2.  To determine to the surface in febrile cases, as by this means the system becomes relieved both of water and solid excreta.

3.  To keep up an increased action of the surface in the different exanthematous diseases, and also in some chronic cutaneous affections.

4.  To cause the skin to take on an augmented action, and by this means relieve certain other organs, especially the kidneys, which may be affected with disease.

5.  To cause the skin to act vicariously when the action of other secreting organs is excessive, as in diabetes insipidus, chronic diarrhoea, &;c.  Combination in the prescribing of sudorifics is often of much service; this is shown in the instance of the compound ipecacuanha powder, a preparation the value of which long experience has confirmed.

SUBCLASS 1.4.4. Medicines affecting the function of the kidneys and urinary organs.

Orders 1.4.4.1 and 1.4.4.2. DIURETICS, LITHONTRIPTICS  Diuretics are medicines which cause an increase in the function of the kidneys, and consequently augment the quantity of the urine.  Lithontriptics are remedies which alter the quality of the urine and prevent the crystallisation and deposit of the ingredients which form gravel and calculi.

Effects of Diuretics and Lithontriptics.

It is difficult to separate the first two classes in the heading, because most of the medicines which alter the character of the urine influence likewise its secretion; and on the other hand those drugs which stimulate the kidneys to increased action, in so doing materially affect its composition; furthermore, there is another group of remedies, usually classed under the head of diuretics, which may in some degree influence the secretion of urine, but which are practically used on account of their action upon the mucous membrane of the urinary passages; these are formed into a separate order.

It will be observed that the class of diuretics is subdivided, and that the remedies in each subclass differ considerably from each other.  In the first are substances which appear to act by their direct action on the renal organs, stimulating them to increased action in their passage through those organs.  Many of the saline diuretics, as nitre, salts of potash, soda, and lithia, appear to act in this manner, as also certain volatile oils, as juniper, turpentine, alcohol, nitrite of ethyle, and cantharides.

In the second subclass, the action of the drugs seems to be of a very different character; digitalis, the principal medicine this placed, acts as a diuretic, probably through its influence upon the heart, and secondarily on the renal circulation, and it is chiefly in cases of disease in which deficient secretion is due to the circulation being disturbed that it proves of value.  Tobacco, if ever of service in such cases, probably causes diuresis in the same manner as also colchicum, scoparium, and squill.

The salts of potash, soda, and lithia, are all of them diuretic, but it is found that lithia salts are more powerful in this respect than the corresponding salts of potash, and potash salts more so than those of soda.

Some of the stimulating diuretics, especially cantharides and turpentine, if given in too large doses, or too long persevered in, produce strangury and the presence of albumen and blood in the urine.

Indirect diuretics are in many cases more advantageously administered than the direct, as the kidneys are often unable to act from congestion or from pressure of fluid contained in the abdomen; and then the free unloading of the vessels by the exhibition of hydragogue purgatives, or local depletion, or the application of counter-irritation to the loins, will promote the secretion of the renal organs more than the mere presence of diuretics in the blood.  Cream of tartar, if given as a hydragogue, acts first by unloading the blood-vessels, and also as a derivative, and subsequently as a direct diuretic, from the absorption of a part of the salt.

Lithontriptics are of at least two kinds; the first and most important group render the urine less acid or alkaline, and enable it to hold the uric acid and urates in solution, or even to dissolve these substances when already deposited.  Lithia is a far more powerful solvent than potash, and potash than soda.  Free dilution of the urine by the exhibition of water in considerable quantities, and at the time of fasting, is of much importance, as it aids greatly the power of the lithontriptic.  It will be remembered that the alkaline salts with a vegetable acid are decomposed and render the urine equally alkaline with those in which the base is united with carbonic acid.

The second class consists of acid remedies, and these are used in cases where the urine is alkaline.  Benzoic acid and benzoate of ammonia appear in the urine as hippuric acid.  Benzoic acid is probably more potent in diminishing the alkaline state of urine than any of the other acids.  The mineral acids, with the exception of phosphoric acid, cannot he given in sufficient quantities to produce much influence upon the reaction of the urinary secretion.

Therapeutic applications of Diuretics and Lithontriptics.

Diuretics are employed for the following purposes:

1.  To cause an increased flow of urine when the renal secretion is deficient.  The selection of the diuretic must depend on the cause of the diminished secretion.  Sometimes a stimulant medicine is required, at other times one of a sedative character.  In eases of dropsy these medicines are peculiarly indicated. 

2. Diuretics are given with an idea of causing elimination of poisons from the blood; and also of matters formed in disease. 

3.  Diuretics are also administered for the purpose of producing a large flow from the kidneys, so as to enable the secreted urine to hold in solution substances which would otherwise crystallise in the urinary passages and form gravel and calculi. Lithontriptics are administered to alter the character of the urine in cases of gravel and calculus; such of these medicines as cause an alkaline condition are indicated where there is a tendency to deposit either uric acid or some little soluble urate; and those which make the urine more acid in cases of phosphatic deposits when an alkaline state of the secretion is present. 

Order 1.4.4.3. Medicines which act specially upon the mucous membrane of the urinary organs.

Acting upon the bladder:

Pareira brava.
Uva ursi.
Chimaphila, or umbellated winter green.
Buchu.
Benzoic acid.
Benzoate of ammonia.
Balsam of Peru. 

Acting upon the urethra:

Copaiba.
Cubebs.
Turpentine. 

Effects of the above remedies.

It is difficult to assign a name for the medicines in the above order, but still for practical purposes it is important that such a grouping should be made.  These remedies certainly appear to produce a distinct and specific action upon the mucous membrane of the urinary passages; some act more upon the bladder itself; some on the urethra.  In the case of benzoic acid and benzoate of ammonia, as well as of balsam of Peru, the benzoic and cinnamic acids become converted into hippuric acid, and alter the state of the urine, as well as of the mucous membrane, by rendering it more acid in reaction, and more stimulating in its properties.

Therapeutic applications of the above remedies.

These remedies are used in disordered conditions of the bladder and urethra; those affecting the bladder in chronic inflammation of the mucous membrane of that organ, often accompanied with alkaline urine; those influencing the urethra, in gonorrhoea and gleet. 

SUBCLASS 1.4.5. Medicines whose action is upon the generative organs.

Order 1.4.5.1. EMMENAGOGUES AND ECBOLICS. Emmenagogues are remedies which are supposed to have the power of exciting the catamenial flow when this is suppressed from any cause; and ecbolics, substances which cause contraction of the uterus, and the expulsion of its contents.

Effects of Emmenagogues and Ecbolics.

Emmenagogues can be well divided into two classes, those which directly affect the uterus, and those which act by removing the state of general system which prevents the manifestation of the catamenial function.  The remedies termed direct emmenagogues produce the first effect; those which are called remote emmenagogues are of a different kind: the first named, the ferruginous salts, act by restoring the blood when in an anaemic state; the rest by stimulating the large bowel, and probably through this the uterus itself.  In many cases a combination of direct and indirect emmenagogues is useful, as amenorrhoea and deficient menstruation are frequently combined.

The group of Ecbolics consists of substances acting especially on the uterus itself; but strong purgatives are apt to excite the uterus to contract. 

Therapeutic applications of Emmenagogues and Ecbolics.

Direct emmenagogues are indicated when the catamenial flow is diminished from a simple sluggishness in the uterine action; the remote, especially the ferruginous class, are useful in the majority of cases of amenorrhoea, for by far the most common cause of the affection is poverty of the blood.  The combination of iron salts with some purgative acting on the rectum and colon, is in such cases most effectual, for a torpid state of uterus is soon produced by impoverished blood; iron remedies the blood, and aloes stimulates indirectly the uterus.

Ecbolics are given when it is desired to cause expulsion of the uterine contents; sometimes this is desirable in cases of disease.  These remedies are often employed for less legitimate purposes.

Orders 1.4.5.2 and 1.4.5.3.  APHRODISIACS AND ANAPHRODISIACS.

Aphrodisiacs are medicines which possess the power of exciting sexual feelings and the venereal function in either sex; and anaphrodisiacs, those which diminish the same.

Effects of Aphrodisiacs and Anaphrodisiacs.

The direct aphrodisiacs appear to act through their stimulant action upon the spinal cord; the indirect by improving the tone of the system generally; of course one or other of these latter are indicated according to the peculiarities of the patient.  Direct anaphrodisiacs on the other hand act as direct sedatives on the spinal cord; the indirect are those which lower the tone of the general system.  The members of the latter group are never administered except for purposes independent of their anaphrodisiac property.

Therapeutic applications of Aphrodisiacs and Anaphrodisiacs.

The uses of these remedies, and the indications for their employment, are sufficiently shown by the names.

SUBCLASS 1.4.6. Medicines which act upon the eyes.

Order 1.4.6.1.  PUPIL DILATORS.
Order 1.4.6.2.  PUPIL CONTRACTORS  Substances which either dilate or contract the pupil.

Effects of the above Substances.

The substances in the above list which dilate the pupil, cause also some alteration in the adjusting power of the eye, producing presbyopia.  They act in the same manner whether applied on or near the eye itself, or taken internally, and probably by stimulating the sympathetic nerves.  Those which contract the pupil produce also myopia, or short-sightedness.  Calabar bean acts both when applied locally and after absorption from the stomach, probably through its influence on the sympathetic nerves.  Opium, on the contrary, has no influence when applied to the eye, but only after its absorption into the general system, and its action is probably upon the third nerve, through the nervous centres.

Therapeutic applications of the above Eye-affecting Remedies.

These substances are used by the ophthalmic surgeon.  Atropine to dilate the pupil for purposes of examination, and to prevent adhesion of the iris in cases of iritis.  Calabar bean is used to counteract the effects of atropine in the above-mentioned application of that drug, and occasionally for other purposes.

DIVISION 2.

External remedies; or medicines which act locally, and are not employed to affect the constitution by becoming absorbed.

Order 2.1. IRRITANTS.

Group 2.1.1.  Rubefacients.
Group 2.1.2.  Epispastics, Vesicants or blistering agents.
Group 2.1.3.  Pustulants.

The substances included under the head of irritants all agree in causing irritation of the skin or other parts to which they are applied, but they differ considerably in the amount of irritation which they produce, and the peculiarities in their action are sufficient to cause them to be arranged into characteristic groups, a division not merely of scientific interest but of practical importance.

Effects of Irritants.

When an irritant is applied to the skin, the amount of action determines much the character of the effect: at first, redness of the skin is produced; if the action is greater, blistering takes place from the cuticle being separated, by the effusion of a serous fluid under the cuticle; and if still more intense, pustulation ensues from the true skin being more deeply implicated and matter thrown out.  Some of the substances named in the list can be made to produce more than one of these effects; for example, ammonia, if applied in a very diluted state, causes merely redness; if stronger, blistering of the skin; and even pustulation is now and then caused by its long-continued application in a very concentrated form: the same remark applies to the glacial acetic acid.  Tartar emetic and croton oil almost always lead to the production of pustules if any marked action is induced: cantharides, on the other hand, usually causes a full epispastic effect.

Therapeutic applications of External Irritants.

The different kinds of irritants are employed to effect various ends:  1.  They are employed as counter-irritants; that is, for the purpose of relieving inflammation or disordered action of internal parts by the derivative effect upon a less important part, the skin: all irritants act more or less in this manner.  2.  Some irritants, namely epispastics, relieve not only from the production of counter-irritation, but also from their causing an effusion of fluid from the vessels of the affected part or its neighbourhood; this effect is often of much value, and far above that of mere counter-irritation.  3.  The pustulants induce a still deeper action, and are sometimes of greater value than vesicants, especially in the treatment of deep-seated and chronic affections.  4.  Many of the irritants are used for their direct effect on diseased parts, as in skin affections of various kinds; and some of them, as the mercurial and iodine preparations, probably induce a specific effect as well as mere local irritation.

Order 2.2. EXTERNAL OR LOCAL SEDATIVES  External sedatives are substances which produce a direct sedative effect upon the part to which they are applied; some, the local anaesthetics, causing complete loss of sensibility.

Effects of External Sedatives.

Practically it may be said that all these substances act as sedatives upon the part to which they are applied, but in their mode of action they differ considerably; some, as hydrocyanic acid, aconite, and veratria, produce a direct sedative effect upon the nerves; some, as belladonna and atropia, probably effect their object by stimulating the vessels to contraction, and thus act as sedatives.  The group of local anaesthetics act, some by contracting the vessels and stopping for a while the circulation, and at the same time produce a diminution or complete loss of the power of sensation of the parts to which they are applied.  For the advantage of the ether spray, the profession is indebted to Dr. Richardson.

Therapeutic applications of External Sedatives.

These remedial agents are employed:

1.  To relieve irritation and inflammatory action.
2.  To allay neuralgic or other pain in the affected parts.
3.  To produce a loss of sensation, and so allow painless operations to be performed.

Order 2.3. EMOLLIENTS  Substances which soften the part to which they are applied, and sooth and diminish irritation.

Effects of Emollients.

The action of these substances appears to be partly of a physical and partly of a physiological character, and need not be dwelt upon.  When used internally, they affect the mucous membranes of the alimentary canal, being then commonly termed Demulcents.

Therapeutic applications of Emollients.

These remedial agents are used to soothe parts which are irritated or inflamed, and to shield them from the action of the air or any foreign influences.

Order 2.4. LOCAL ASTRINGENTS AND STYPTICS.  Substances which brace up or produce an astringent effect upon the parts to which they are applied; when used to arrest haemorrhage they are called styptics.

Effects of Local Astringents and Styptics.

The same as those of the general astringents; and, as will be seen by the list, the same substances are employed.

Therapeutic applications of Local Astringents and Styptics

These remedial agents are employed:-

1. To arrest haemorrhage by application to the part.
2. To check discharges, either from an increase of normal secretion, or diseased secretion; often used in the form of injection to affect mucous membranes, as in leucorrhoea and gleet.
3. To give tone when applied to prolapsed parts.
4. To produce an alterative effect upon the skin in various forms of cutaneous disease.

Order 2.5. CAUSTICS AND ESCHAROTICS  Substances which destroy the parts with which they come in contact; the stronger caustics produce an eschar, and are termed escharotics.

Effects of Caustics and Escharotics.

All the substances contained in the above list produce a chemical rather than a physiological action upon the parts to which they are applied.  On dead animal tissues they act even more powerfully than on the living body.  The effect of these substances, as will be seen by studying their chemical properties, differs considerably; some act by their intense affinity for water, others by forming compounds with the albuminous principles of the tissues.

Therapeutic applications of Caustics and Escharotics.

These remedial agents are employed:
1. To destroy poison, as of serpents, rabid animals, and syphilis.
2. To remove exuberant and morbid growths, as in excessive granulations, worms, polypi, and cancerous deposits; also to improve the character of ulcerated surfaces.
3. To act on the healthy skin so as to form issues and to open abscesses.

DIVISION 3.

Order 3.1. ANTIDOTES.  Antidotes are substances which counteract the injurious influence of poisons introduced into the body.  Antidotes may be divided into direct and indirect antidotes; the former neutralizing or destroying the injurious action of the poison on meeting it in the system; the latter counteracting the injurious physiological effects of the drug.  The following is a list of some of the most important antidotes to the chief poisons.

Indirect Antidotes. Substances which physiologically counteract the baneful influences of the respective poisons.

Order 3.2. DISINFECTANTS AND ANTISEPTICS.  Disinfectants are substances which destroy one or all of the poisons capable of producing diseases, and remove disagreeable gases and odours by decomposing both them and the bodies from which they proceed. In the British Pharmacopoeia the following disinfectants are contained:

Antiseptics are substances which prevent chemical change by destroying the activity of infecting matters, without of necessity altering their chemical composition. In this restricted sense they have been named colytics.

Of the substances in the above list, many, as chloride of zinc, perchloride of iron, chloride of sodium, corrosive sublimate, arsenic, and sulphate of copper, have very little influence on animal poisons, but simply preserve organic matters from decomposition.  Free sulphurous acid has the advantage of being not only an antiseptic but also a deodorizer.  The essential oils also possess some preservative powers.

History of Medicine
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