Chapter IV: Of Mechanical Remedies (1)

This subdivision includes those classes of remedies, whose operation depends entirely upon _mechanical_ principles; and we must agree with Dr. Murray in considering them as the least important of all the articles which we have enumerated, and which cannot therefore constitute objects of elaborate inquiry.

ANTHELMINTICS:

Remedies which expel worms[234] from the intestinal canal.

It has been already stated, (_page 90_) that certain bodies have the power of increasing the peristaltic motions of the intestinal canal, by operating as mechanical stimulants upon its fibres; in this manner the filings of tin and iron, or the irritating down which covers the pods of the _Dolichos Pruriens_, are supposed to act in dislodging and evacuating the worms from the intestines. But there is a variety of remedies employed as vermifuges, which must owe their effects to a very different mode of operation; _Bitters_ for instance appear to prove an absolute poison[235] to these animals, while they, at the same time, give an increased tone to the organs of digestion; from whose debility the generation of worms would seem to arise. Other remedies, again, obviously depend upon their simple cathartic property, for the powers which they possess in the evacuation of worms. See _Terebinthinæ Oleum_—_Cambogia_.

In the cure of Ascarides the local application of the remedy becomes necessary, in the form of glyster, and which acts both _mechanically_ in washing out the gut, and _medicinally_ in proving obnoxious to the animals. According to the experience of some of our best practitioners, a strong decoction of the _Semina Santonici_ proves most efficacious upon these occasions.

DEMULCENTS:

Medicines which are capable of shielding sensible surfaces from the action of acrid matter, by involving it in a mild and viscid medium.

It cannot be denied that where these remedies admit of direct application, considerable benefit may arise; in the progress of a catarrh, we have all experienced the relief that may be occasioned by lubricating the fauces with demulcents, which, by soothing the top of the trachea, quiets, by a kind of contiguous sympathy, the whole pulmonary structure; in certain states of intestinal irritation, the same remedies have furnished considerable benefit, and in ophthalmia, relief has been obtained by the application of a demulcent to the inflamed conjunctiva, by which it is defended from the irritation of the tears; see also _Formula 61_; but in parts beyond the reach of the first passages, and to which no fluid can arrive but through the medium of the secretions, it is very difficult to explain the principle upon which their beneficial operation can depend; and it seems indeed highly probable that they act in such cases as simple diluents, for the process of digestion must necessarily deprive them of their characteristic viscidity. The administration of demulcent drinks in gonorrhæa is probably of no farther service in assuaging the _ardor urinæ_, than an equivalent quantity of pure water; although Dr. Murray observes, “it is sufficiently certain, that many substances, which undergo the process of digestion, are afterwards separated in their entire state from the blood, by particular secreting organs; and there is, continues he, no gland which has this power more particularly than the kidneys; substances received into the stomach and digested, afterwards passing off in the urine with all their peculiar properties.” This is undoubtedly very true, but mucilaginous substances rarely or never pass off in this manner; if they evade the assimilative functions, they pass through the alimentary canal, and are thus eliminated. I can state, as the result of experiment, that the urine undergoes no change except in the relative proportion of its water, by the copious and repeated administration of mild mucilages. Dr. Saunders has very justly remarked that the long list of _Ptisans_, _Decoctions_, _&c._ usually prescribed upon these occasions, generally owe their virtues to the watery diluent itself.

The pharmaceutical applications of this class of medicines constitute, perhaps, not the least part of their value, by which we are enabled to introduce acrid substances into the stomach with safety and effect; but such services will more properly fall under our notice in a future part of the work.

DILUENTS:

Watery liquors, which increase the fluidity of the blood, and render several of the secreted and excreted fluids less viscid.

There are certainly few remedies whose operation is more simple, obvious, or important; and yet there are scarcely any whose value has been more mistaken, or whose application has been so frequently perverted through the suggestions of false theory; water is the universal beverage of animals, and the necessity of its supply is indicated by thirst, a sensation which in excess, is borne with less tranquillity even than that of hunger; in certain morbid states of the body its presence is to be regarded as indicating the necessity of copious potation; and yet how often has the prejudiced physician, under such circumstances, aggravated the pressure of disease, by adding the sufferings of Tantalus. In febrile affections, the irritation of thirst tends to keep up the disease, and hence diluents, besides the other beneficial effects which they may produce, must be regarded as important remedies. There are also diseases of the alimentary canal which may be removed by the same agents; when water is conveyed into the intestines it will have a tendency, by mixing with, and diluting the biliary secretion, to diminish its acrimony, and thus to obviate a source of morbid irritation; the dilution of the chyme and chyle may also have a salutary tendency, and favour the absorption of the finer and more nutritive parts of the lacteals; and by increasing the fluidity of the mass, expedite the numerous combinations which it is destined to undergo. The blood itself is also thus modified in its fluidity; although it has been very truly observed that in healthy bodies, or such as are without any obstruction of the excretions, an unusual distension of the vessels cannot be produced, or at least long subsist; for it is evident that such an increased quantity of water in the blood will immediately pass off by one or other of the excretions; this effect, however, in itself, renders the operation of diluents of signal service in the treatment of the disease; in consequence, for instance, of their disposition to pass off by urine, they furnish valuable resources in diseases of the urinary organs, allaying the pain of strangury, and the irritation from an inflamed bladder. From these observations, the practitioner will be led to appreciate the value of diluents; and many of the beneficial effects which are daily experienced from the copious potation of mineral waters, are, without doubt, to be wholly attributed to simple dilution. See _Aqua_.

It is here necessary to say a few words upon the misapplication of this order of remedies. Dr. Davy found by experiment that when an animal is bled to death, the last portions of blood that flow are of a much lower specific gravity than that which flows first, in consequence of the former containing more water, which it may be inferred was derived by the increased activity of the absorbents, exerted chiefly on mucous and serous membranes. Since then venesection promotes and accelerates absorption,[236] it is clear that, in inflammatory diseases, where we have recourse to blood-letting, in order to diminish the volume of circulating fluids, we ought not to suffer the patient to indulge in an unrestrained use of liquids, which he eagerly demands to satisfy a thirst which, in all probability, is the natural consequence of increased absorption. In such cases, it is often better to take liquids in small divided doses, which will have the effect of moderating the thirst, without overloading the arterial system, and bringing on that tension and plenitude which are liable to be produced by swallowing too large a proportion of liquids.

In the use of water upon such occasions, it may moreover be observed, that its temperature ought to be attended to; as a general rule it may be laid down, that in the _cold_ stage it should be hot, in the _hot_, cold, and in the _sweating_, tepid.

With regard to the value of diluents, as capable of promoting the operation of other remedies, many observations of great practical importance might be adduced; but this subject will be more properly elucidated when we come to consider the influence of solubility in modifying the activity of medicinal substances, and which constitutes a very curious and interesting object of chemico-medical enquiry.

While speaking of Diluents it may be cursorily noticed, that water appears, under certain circumstances of the body, to suffer decomposition, and to have its elements appropriated to new combinations. Count Rumford has endeavoured to prove, that the surprisingly small quantity of solid food which is sufficient for nourishment, when converted into rich and palatable soup, is owing to the culinary process having prepared the water for chemical decomposition,[237] and that this is ultimately effected during the act of Digestion.[238] It cannot be denied that the exorbitant potation of water has a tendency to produce fat, but this may depend upon the vascular distention which is thus occasioned. Gin drinkers, before they become materially injured by the habit, grow extremely corpulent, as may often be witnessed in unfortunate cyprians of the lower orders. Can the hydrogen of the spirit contribute to this effect?

EMOLLIENTS:

Substances whose application diminishes the force of cohesion in the particles of the solid matter of the human body, and thereby renders them more lax and flexible.

According to this definition, which we derive from Dr. Cullen, the primary operation of emollients would appear to be purely mechanical, for they are insinuated into the matter of the solid fibre, and either diminish its density, or lessen the friction between its particles; this explanation will undoubtedly apply to those emollients which consist of unctuous bodies, and which are introduced into the animal fibre by friction; but it is evident that the beneficial effects of _Cataplasms_ and _Fomentations_ cannot be so explained; for in these instances, none of the materials can be absorbed through the entire cuticle; and yet the relaxation and consequent ease which such warm applications produce on inflamed surfaces is very considerable, but it must be wholly attributed to the relaxing effects of warmth and moisture upon the extreme vessels of the surface, propagated by _contiguous sympathy_ to the deeper seated organs.

The operation of those substances which afford relief to excoriated surfaces by their bland qualities, as mucilaginous lotions in erysipelatous affections, is too obvious to require explanation.

Having thus investigated the manner in which medicinal substances produce their effects upon the living system, we shall be better prepared to appreciate the advantages which are to be derived from their combination with each other, and to escape the too common error of uniting in one formula, remedies which are rendered adverse by the incompatibility of their physiological actions.

ON THE

THEORY AND ART

OF

PRESCRIBING.

“_To know
“That which before us lies in daily life,
“Is the prime wisdom._”
MILTON.

ON THE
THEORY AND ART
OF
PRESCRIBING.

OF MEDICINAL COMBINATION.

“_Variorum mixtura novas sæpe vires generet, in simplicibus nequaquam
reperiundas longe saluberrimas._”

GAUBIUS.

It is a truth universally admitted, that the arm of physic has derived much additional power and increased energy, from the resources which are furnished by the mixture and combination of medicinal bodies. I by no means intend to insinuate that the physician cannot frequently fulfil his most important indications by the administration of one simple remedy; I only contend that, in many cases, by its scientific combination with other medicines, it will not only act with greater certainty and less inconvenience, but that its sphere of influence may be thus more widely extended, and its powers so modified or changed, as to give rise to a remedy of new powers. Such a theory is amply justified by the state of combination in which certain medicinal principles are found in our more efficient vegetable remedies, while the medicinal practice founded upon it is thus, as it were, sanctioned by Nature’s own prescriptions; enter but her laboratory, and you will soon be satisfied, that many of her potent remedies do not owe their valuable powers to any one specific ingredient, but to the combined or modified energies of various, and sometimes opposite principles. This view of the subject opens an interesting and unexplored field[239] of medical and chemical research, and I shall endeavour to avail myself of the novelties its investigation may present, and of the hints it may suggest for the improvement of _extemporaneous combination_. By contemplating the laws by which Nature effects her wise purposes, we may learn to emulate her processes, and even in some cases to correct and assist her operations:[240] such at least has been the happy result of our labours in the other departments of natural knowledge. It is said for instance that by observing the means used by nature for preventing the diffusion of light in the eye-ball, Euler derived an important hint for the improvement of his telescope; and more lately, the structure of the crystalline humour of the eye has been successfully imitated in the invention of achromatic lenses. On the other hand, it is hardly necessary to observe to what extent these instruments of art are capable of improving and multiplying the powers of that natural organ, to the contemplation of whose structure and functions, we are, as I have just stated, so greatly indebted for their origin and perfection. So shall I endeavour to shew, in the progress of this work, that the combinations of nature, as exemplified in her more valuable remedies, are capable, if properly studied, of suggesting many important hints for improving the arrangements of art; while art in return may frequently supply the defects, or extend the advantages of natural compounds.

AN ANALYSIS
OF
THE OBJECTS TO BE OBTAINED BY MIXING AND COMBINING MEDICINAL SUBSTANCES.

The objects to be attained, and the resources which are furnished, by MEDICINAL COMBINATION, together with the different modes of its operation, and the laws by which it is governed, may with much practical advantage be arranged in the following order.

I.
TO PROMOTE THE ACTION OF THE BASIS, OR PRINCIPAL MEDICINE.

A.—_By combining together several different Forms, or Preparations, of the same substance_.

The utility of such a combination is obvious, whenever we desire the full and general effects of _all_ the principles of a medicinal body in solution; thus, where the _Bark_ is required in the cure of an intermittent fever, and the stomach will not allow the exhibition of the powder, it will be eligible to conjoin in one formula, the tincture, decoction, and extract, as exemplified by _Formulæ 42, 126, 127_. The necessity of such a combination may be expressed by the following canon. _Whenever the chemical nature of the medicinal substance will not admit of the full solution of all its active principles in any_ ONE _Solvent_, _and its exhibition in substance is at the same time impracticable_. For farther illustrations see _Form. 2, 25, 33, 38, 70, 109_.

Practitoners, probably without having reasoned upon the theory, have very generally adopted the practice, of combining the different solutions of the same substance; for in the prescriptions of practical physicians we commonly find, that the decoction or infusion of a vegetable remedy is quickened by a certain portion of a corresponding tincture.

B.—_By combining the Basis with Substances which are of the_ SAME NATURE, _that is, which are_ INDIVIDUALLY _capable of producing the same effect, but with less energy than when in combination with each other._

Dr. FORDYCE first established the existence of the singular and important law, that _a combination of similar[241] remedies will produce a more certain, speedy, and considerable effect than an equivalent dose of any single one_; a fact which does not appear to have been known to any ancient physician. The earliest mention of it that I can find is by VALISNIERI, the favourite pupil of Malpighi, who filled the medical chair at Padua in 1711, nearly ninety years before Fordyce published his valuable memoir on the combination of medicines, but he does not attempt any generalization[242] of the subject; he merely states, as the result of careful experiments, that twelve drachms of _Cassia Pulp_ are about equivalent in purgative strength to four ounces of _Manna_; and yet, says he, if we give eight drachms of _Cassia Pulp_, in combination with four drachms of _Manna_, we obtain double the effect! How, adds the professor, can this possibly happen? Surely the very contrary _ought_ to obtain, since four drachms of _Cassia_ are much more than equivalent to an equal weight of _Manna_; the strength of the former being to that of the latter as 8 to 3.

The truth of this law of medicinal combination must be continually felt by the practitioner in the ordinary routine of his practice, viz.

NARCOTICS will better fulfil the intention of allaying irritation and pain, when composed of several of such medicines in combination, than when they consist of any single one, even should the dose, in this latter case, be increased. See _Formulæ 3, 4, 5_.

ANTISPASMODICS acquire increased efficacy by the application of the same principle. _Form. 20, 21, 22, 23, 24, 25_.

BITTER TONICS are also thus exalted, see _Form. 39, 40, 41_. The beneficial effects, however, which arise from combinations of this kind will admit of a satisfactory explanation upon another principle; we may, for instance, consider them as medicines, differing from each other in their composition, and producing by their union an assemblage of bitter, astringent, and aromatic principles.

AROMATIC and DIFFUSIBLE STIMULANTS. There are perhaps no remedies which receive greater mutual benefit be intermixture with each other, than the individuals which compose this class; for they not only thus acquire increased force and efficacy, but at the same time they lose much of their acrimony; if, for instance, any one spice, as the dried capsule of the _Capsicum_, be taken into the stomach, it will excite a sense of heat and pain; in like manner will a quantity of _Black Pepper_; but if an equivalent quantity of these two stimulants be given in combination with each other, no such sense of pain is produced, but, on the contrary, a pleasant warmth is experienced, and a genial glow felt over the whole body; and if a greater number of spices be joined together, the chance of pain and inflammation being produced is still farther diminished. The truth of this law is also strikingly illustrated, as Dr. Fordyce has observed, by that universal maxim in cookery, _never to employ one spice, if more can be procured_; the object, in this case, being to make the stomach bear a large quantity of food without nausea.[243] This same principle also finds an illustration of its importance, as it regards the class of stimulants, in the following preparations of our Pharmacopœia, viz. “_Pulvis Cinnamomi Compositus_; _Infusum Armoraciæ compositum_; _Infusum Aurantii Compositum_; _Spiritus Lavendulæ compositus_; _Tinctura Cinchonæ composita_; _Tinctura Valeriana Ammoniata_; and the _Confectio Opii_, the elegant and scientific substitute for the celebrated _Mithridate_ or _Theriaca_. The practitioner is also referred to _Form. 45, 47_, and to _Allii Radix_.”

The local action of these stimulants would appear to be placed under the dominion of the same law, and perhaps the origin of the custom, so long observed, of mixing together the varieties of snuff, may thus receive a plausible and philosophical explanation; certain it is that by such combination the harsh pungency of each ingredient will be diminished, whilst the general potency of the application, in exciting the nerves, will be increased, and rendered more grateful; the same principle will direct the formation of safe and efficient plaisters and lotions; the _Emplastrum Cumini_ of the London, and the _Emplastrum Aromaticum_ of the Dublin Pharmacopœia, offer examples of its judicious application.

ASTRINGENTS. For illustrations see _Form. 51, 58_.

EMETICS are certainly more efficient when composed of _Ipecacuan_ united with _Tartarized Antimony_, or _Sulphate of Zinc_, than when they simply consist of any one of such substances in an equivalent dose. See _Form. 63, 65_.

CATHARTICS not only acquire a very great increase of power by combination with each other, but they are at the same time rendered less irritating in their operation; the _Extractum Colocynthidis compositum_ affords an excellent example of a compound purgative mass being much more active and manageable, and less liable to irritate, than any one of its components separately taken. Additional examples of this fact are furnished by _Formulæ 70, 76, 78, 79, 81, 88_. In many cases, however, the fact of purgatives thus accelerating and correcting each other’s operation may be explained by considering them as substances endowed with different powers, as already demonstrated, (p. 88), and which will be more fully considered in the third division of this Essay.

DIURETICS. Under this class of medicinal agents it may be observed that, _whenever a medicine is liable to produce effects different from those we desire, its combination with similar remedies is particularly eligible_, by which the action of the basis may be directed and fixed; thus the individuals which compose the class of Diuretics are uncertain in their operation, and disposed when exhibited singly to produce diaphoretic, and other contrary effects; it is, therefore, in such cases, highly judicious to unite several of them in one Formula, by which we increase their powers, and are more likely to ensure their operation. _Formulæ 101, 103, 108, 109, 110, 111, 115_, are constructed upon this principle.

DIAPHORETICS. Our maxim, “VIS UNITA FORTIOR,” certainly applies with equal truth to this class of medicinal agents. _Form. 122, 124_.

EXPECTORANTS. More is frequently to be gained by the co-operation of these remedies than can be obtained by the exhibition of them separately, as in _Form. 134, 135_.

DEMULCENTS do not appear to obtain any other benefit from combination than, occasionally, a convenience and efficacy of application arising from a suitable degree of consistence and solubility. See article “_Trochisci_.”

The operation of the law which has thus formed the first object of this inquiry, will be found, like every other, to have a natural and well defined limit; it is easy to perceive that by multiplying the number of ingredients too far, we shall either so increase the quantity and bulk of the medicine as to render it nauseous and cumbersome, or so reduce the dose of each constituent as to fritter away the force and energy of the combination.

The propriety of combining _several_ stimulants, of the diffusible class, in _one_ formula, has been questioned on different grounds. Dr. Chapman, in his work on Therapeutics, adduces some arguments on this point, which, although they fail in establishing his general position, certainly suggest an important exception to the practice in question; “by directing,” says he, “stimulating remedies, _separately_, we shall economise our resources in many lingering diseases.” The justness of this statement must be admitted to its fullest extent, and practitioners will, on certain occasions, do well to act in conformity with the views that suggested it; for instance, in the feeble forms of protracted fevers, where the indications are to be met with the continued action of stimulants, it will certainly be salutary to alternate the use of _camphor_, _ammonia_, and other remedies of a similar nature, in preference to presenting them all at once in combination, so that the system may not lose its susceptibility by the continued impression of the same stimulant; the same motive should induce us, on particular occasions, to employ in succession different narcotics, for each of them affects sensibility in its own peculiar manner.[244] The nervous system, as _Richerand_ has very justly observed, may be compared to a soil, rich in different juices, and which requires the cultivator to plant the germs of a diversified vegetation to develope the whole of its fecundity; to insure a perpetual return, therefore, it will be right to sow a succession of different seeds. Hoffman also has offered us some advice upon this subject; he directs us in the treatment of chronic diseases to suspend the administration of remedies, at intervals, and afterwards to resume them, lest the system should become _habituated_, and ultimately _insensible_ to their influence.

But there remains for our investigation a still more important precaution respecting this law of medicinal combination;—that, in combining substances in the manner, and for the object just related, the practitioner should be well satisfied that their medicinal virtues are in reality _practically_ SIMILAR, or he will fall into an error of the most fatal tendency; it has been already shewn, and I hope I shall not be considered tedious by again directing the reader’s attention to the fact, that medicines are not necessarily similar because they have been arranged in the same artificial division of remedies; in order to establish a perfect similarity _their operations must be found by experience to continue similar under every condition of the human body; and that, moreover, they must owe such similarity to modes of operation which are compatible with each other, and consonant with the general mode of cure_; we have only to refer to the history of Diuretics (_page 92_) for a full illustration of this important truth; thus _Squill_, _Calomel_, and _Digitalis_, are each powerful Diuretics, but nevertheless they cannot be considered _similar_ remedies, since _Digitalis_ will entirely fail in its effects in the very cases that _Calomel and Squill_ succeed; and _Squill_ will prove inert when _Digitalis_ is capable of producing the most powerful influence; this arises from their modes of operation being dissimilar, and consequently requiring for their success such different states of the living system. _Squill_, it will be seen, acts _primarily_ on the urinary organs, by stimulating the secreting vessels of the kidneys; _Mercury_, on the contrary, acts primarily on the absorbents, and _secondarily_ on the kidneys; whereas _Digitalis_ produces its effects by diminishing arterial action, and increasing that of absorption.

Dr. Blackall, in his “Observations upon the Cure of Dropsies,” has offered some remarks so valuable in themselves, and so illustrative of this important subject, that I shall take leave to quote the passage. “Many physicians,” he observes, “are fond of combining _Squill_, _Calomel_, and _Digitalis_, as a diuretic in dropsy; a practice unsafe, and not very decidedly possessing the merit even of being consistent. _Digitalis_ greatly depresses the action of the heart and arteries, and controls the circulation, and it seems most unreasonable to believe that its curative powers can be independent of such an effect; on the other hand, _Mercury_, if it does not pass off quickly, is always exciting fever, and raising and hardening the pulse; speaking from experience, where the urine is coaguable, and _Digitalis_ agrees, both the others are, often at least, positively injurious. On the contrary, where the urine is foul, and not coaguable, and _Squills_ with _Calomel_ render service, I have on that very account, made less trial of Digitalis, and cannot therefore speak of it from much experience.” See _Form. 103_, and the _note_ thereon.

The individual medicines which compose the class of DIAPHORETICS vary no less in their primary operations, as the synoptical arrangement at _page 99_ very fully exemplifies; thus, in the cure of intermittent fevers, diaphoretics are useful both in the paroxysm, and during the intermission; in the first case they shorten its duration; in the second they support the tone of the extreme vessels, and prevent its recurrence; but in these opposite states of disease a very different kind of diaphoretic is required—to fulfil the first indication, a cooling and relaxing one is necessary; to answer the second, the stimulating diaphoretic is exacted; the one may be said to _solicit_, the other to _extort_, perspiration. So again EMMENAGOGUES can only be considered relative agents, since the suppression of the catamenia may depend upon, or be connected with, very different states of the system; in some cases with a diminished, and in others with an increased state of excitement; for on many occasions the suppression of the menses is the effect, and not the cause of disease; _Boerhaave_ has very justly observed, that it is a most dangerous error to ascribe all the diseases of young females to a retention of the catamenia, which often do not appear because the patients are disordered from other causes. If, therefore, we were to attempt a combination of the several medicines which have gained reputation as _Emmenagogues_, it is very obvious, that we should bring together an assemblage of adverse and incompatible remedies; nor would the physician be less inconsistent were he to combine EXPECTORANTS, without a due regard to their modes of operation; it is only necessary to observe their classification, as presented at page 102, to become satisfied how greatly the success of such remedies must depend upon their scientific adaptation to each particular case.

The class of ANTISPASMODICS may likewise embrace remedies of the most opposite tendency, for spasm may occur under the most opposite circumstances—in an extreme condition of weakness, as in nervous affections, and in an highly excited state, as in cholic, &c.; it is hardly necessary, therefore, to point out the mischief that must arise from the fortuitous and indiscriminate admixture of the individual substances which are thus unavoidably arranged in the same artificial classification. _Bark_ and _Steel_ are also too often considered as equivalent _Tonics_; in Dropsy, says Dr. Blackall, it is far otherwise, the former being infinitely to be preferred after the dropsy of young persons, of acute disease, and of sound stamina; the latter being suited to a vitiated rather than to a feeble habit, and indicated more by a pale sallow complexion, and a want of red colour in the blood, as shewn by the paleness of the lips, than by any other signs. Need we then adduce farther illustrations of the obvious but important fact, that the terms employed to denote the different classes of remedies are frequently but relative ones, expressive of effects which are produced only in reference to a particular state of the living body? and as this necessarily varies in different states of health and disease, it follows that medicines are convertible agents, and that when we attempt to institute general rules respecting their administration, without taking into consideration the constitution and circumstances of the patient upon whom they are to operate, we shall generally be disappointed in the result. We may say of medicines what Van Swieten said of diet, “to assert that such, or such a thing be wholesome, without a knowledge of the condition of the person for whom it is intended, is like a sailor pronouncing the wind to be fair without knowing to what port the vessel is bound.” Boerhaave was so fully impressed with this truth that he exclaimed, “_nullum ego cognosco remedium, nisi quod tempestivo usu fiat tale_.”

Although medicines which produce the same ultimate effects by modes of operation obviously different, cannot be considered SIMILAR, in the sense affixed to the term in the present section, yet if these different modes of operation be not physiologically incompatible with each other, the union of such remedies may not only be admissible, but even useful; and it will, accordingly, constitute an object of inquiry in a succeeding section. (III. A.)

C.—_By combining the Basis with Substances of a_ DIFFERENT NATURE, _and which do not exert any Chemical influence upon it, but are found, by experience, to be capable of rendering the Stomach, or System, or any particular organ, more susceptible of its action_.

Thus it is that the system is rendered more susceptible of the influence of Mercury, by combining it with Antimony and Opium.[245] Where the stomach is insensible to impressions, the exhibition of Opium previous to, or in combination with, any active medicine, often assists its operation; this is remarkably striking in some states of mania, when emetics will fail, unless the stomach be previously influenced and prepared by a narcotic; indeed, in ordinary cases of inirritability of stomach, the addition of a small quantity of opium will often render an emetic active.[246]

So again the system, when it is in that particular condition which is indicated by a hot and dry skin, is unsusceptible of the expectorant powers of Squill, unless it be in union with antimony or some powerful diaphoretic, (_Form. 134_.) Squill is by no means disposed to act upon the urinary organs, when exhibited singly; but calomel, and some other mercurial preparations,[247] when in conjunction with it, appear to direct its influence to the kidneys, and to render these organs more susceptible of its operation; (103, 106.) Upon the same principle, _Antimonial Wine_ quickens the operation of saline cathartics (69); _Opium_ increases the sudorific powers of _Antimony_ (124); and the purgative operation of _Jalap_ is promoted by _Ipecacuan_ (84). Dr. Aikin asserts that fifteen grains of the former purgative when combined with two or three grains of the latter root, will purge more than double that quantity of Jalap when administered without such an adjunct.

Sir John Pringle speaks of the advantages which may be obtained by combining an alkali with a bitter infusion, by which the diuretic effects of the former will be increased, while the latter is calculated to remove any gastric debility, and to impart a general tone to the body: there is no doubt but that _Bitters_, from their invigorating influence upon the _primæ viæ_, (_see page 78_) increase the effects of remedies whose operation is connected with changes _in transitu_, or with absorption, as in the exhibition of certain diuretics;[248] they also frequently render the stomach and bowels more susceptible of bodies that act by impression, as purgatives, emetics, &c.

We may discover the operation of such a principle in some of the more active compounds presented to us by nature: many herbs owe their efficacy to a cause of this kind. _Elaterium_, as I have ascertained by experiment, contains a purgative element, _sui generis_, (_Elatin_) and a bitter principle, which in itself is quite inert, and yet its presence in the compound renders the alimentary canal more susceptible of the impression of the active ingredient, and therefore increases its force. See _Extract_. _Elaterii._ The history of _Senna_ will afford some interesting facts in farther elucidation of this subject; the leaves of this plant, like _Elaterium_, appear to contain an active principle, in combination with a bitter, which latter ingredient, although destitute of purgative properties, considerably increases those of the former; for if this be removed, as happens when Senna is transplanted into the south of France, the purgative principle is weakened, but may be again restored by the artificial addition of some bitter extractive. The fruit or pods of Senna[249] contain only the purgative principle, and are therefore comparatively feeble, unless the defect be compensated by art. Dr. Cullen has observed that a much smaller quantity of the leaves is required for a dose if they be infused in company with some bitter plant; and it has been found that the watery infusion of _Rhubarb_ is rendered more purgative by the addition of _Calumba_.

The experiments of Seguin have established beyond all doubt that the active principle of vegetable astringents is a peculiar element, to which the name of _Tannin_ has been given; but the efficacy of this ingredient is undoubtedly enhanced by the presence of the gallic acid with which it is usually associated, although this acid, when separated from the native combination, is incapable of producing the least astringent effect; that peculiar flavour which we so commonly experience in unripe fruits, and which we designate by the term _acerbness_, is the result of a combination of the astringent principle with some vegetable acid. The relative sweetness of sugar, when in different degrees of purity, depends upon the operation of the same law of combination; _pure sugar_, as Dr. Mac Culloch has very justly observed, however paradoxical it may appear, _is not so sweet as that which is impure_; the sweetness of _melasses_, compared with that of refined sugar, is too well known to require more than a bare mention; the vegetable extractive matter in this case, increases the effect of the saccharine principle with which it is combined; for the same reason grapes, differing very materially in their proportion of saccharine matter, may seem _to the taste_ equally sweet, and such in fact is the case on comparing the luscious grapes of Spain, with the _Chasselas_ of Paris; and yet the vinous produce is entirely different, the result of the one being a sweet and luscious wine, while that of the other is hard and dry, because, in truth, these grapes contain very different proportions of sugar; and however powerfully the extractive matter may modify the effects of this principle upon the palate and organs of taste, it cannot alter the quantity of alcohol resulting from its fermentation.[250] Crystallized sugar also appears less sweet to the taste than loaf sugar, but this may depend upon the different state of aggregation, and, consequently, the different degrees of solubility possessed by the sugar in these two forms.

In some cases, the addition of certain bodies will induce the absorbents to admit and carry into the circulation remedies which, in a more simple state, they would reject as injurious; this position is supported by the fact of mercury being more readily absorbed when in combination with animal matter, see _Ung: Hydrarg:_ and it is probable that iron, in the form of a _tanno-gallate_, will be more acceptable than when presented in a more purely mineral state: see _Ferri Sulphas_.

Does it not therefore appear from the preceding remarks, that _certain elements exist in the composition of vegetable remedies, as furnished by nature, which, although individually inert, confer additional strength and impulse upon the principle of activity with which they are associated_.[251]

The solutions of saline cathartics appear likewise to gain an accession of power and celerity of operation by impregnation with _Carbonic acid gas_, depending probably upon the intestines thus receiving a degree of distention favourable to the action of the salt, (19, 23.) Certain it is that the operation of emetics, as well as that of glysters, is materially increased by the stimulus of distention.

In enumerating the methods to be adopted for increasing the energies of a remedy, by rendering the system more susceptible of its action, it is right to know that, under certain circumstances, Venesection deserves a distinguished rank amongst the ADJUVANTIA. The fact is strikingly discovered in the exhibition of _Mercurial[252] Preparations_, and some other alterative medicines. Whether the “_Vis Conservatrix_,” which Nature, when in a state of health and vigour, opposes to the admission of poisonous substances into the circulation, be overcome by blood-letting, is a question which I shall leave others to decide; but thus much reiterated practice has taught me, that the system in a strong and healthy condition frequently is overcome the moment the stomach becomes deranged, the circulation languid, or the general tone of the system impaired. I have frequently seen this during my Hospital practice: if a patient who has been using mercurial friction, or taking the preparations of that metal without effect, be transferred into a close and unhealthy ward, his appetite soon fails, the tongue becomes furred, and the system instantly yields to the influence of the remedy. Nauseating doses of _antimony_[253] frequently repeated, or the accidental supervention of any disease of debility, will be attended with the same phenomena. My practice has also afforded me an opportunity of appreciating the debilitating effects of despondency in a case of this description; a patient had been taking mercurial medicines, and using frictions for a considerable period, without any apparent effect: under these circumstances he was abruptly told that he would fall a victim to his disease; the unhappy man experienced an unusual shock at this opinion, and in a few hours became violently salivated.[254]

VENESECTION, moreover, increases the effects of cathartic medicines. I have often noticed this fact in contending with a plethoric diathesis; whenever the bleeding preceded the purgative, the effects of the latter have been uniformly more speedy and considerable; in obstinate constipation the same fact has been observed, and mild remedies have been known to act more powerfully, when preceded by blood-letting, than potent ones have when exhibited antecedent to it. Venesection has certainly an extraordinary power in awakening the susceptibility of the _primæ viæ_ to remedial impressions; in some diseases, as in the _Cynanche Trachealis_, or Croup, so great is the insensibility of the stomach, that Emetics frequently fail in their effects; and Dr. Hamilton has given as much as a hundred grains of _Calomel_ in the twenty-four hours: in such cases previous venesection affords most extraordinary assistance. Dr. Fothergill also remarks that emetics are more beneficial after bleeding, (_Dissert. Med. Inaug. de Emet. usu._) The effects of _Bark_, _Steel_, and other tonics, are certainly influenced in the same manner; whether in any case it may be prudent or judicious to have recourse to such a practice, is a question not immediately connected with the present inquiry.

Limited must have been the experience of that practitioner who has not frequently witnessed the utility of Venesection in producing a state of system favourable to the operation of various remedies. In acute diseases, how frequently does an opiate succeed in allaying irritation after copious bleeding, which could not be made to occasion any beneficial influence previous to that operation? In Pneumonia I have repeatedly seen such a plan of treatment act like a charm upon the patient.

PURGATIVES also awaken the susceptibility of the body to mercurial impressions, and it is remarked by Dr. Chapman that this practice affords a resource which rarely disappoints the practitioner. This class of remedies moreover seems capable of exalting the efficacy, and indeed of accelerating the benefit to be derived from many alteratives, when administered _previous_ to the exhibition of these latter substances; the advantages of a course of Steel medicines are undoubtedly increased by such means. The febrifugous and antiseptic properties of diluted muriatic acid (see _Form. 145_.) are inconsiderable, unless its exhibition be accompanied with cathartics. I beg to refer the practitioner to some cases published by me in the _Medical and Physical Journal for December_, 1809, in further illustration of these views. Experience enables me also to state that _Diuretics_ are considerably assisted by similar means, having many instances in my case book of the failure of these agents before, and their successful operation after, the exhibition of a cathartic. Dr. Darwin observes that “_Absorptions are always increased by Inanition_,” and in support of this position refers to the frequent advantage derived from evacuations in the cure of ulcers. I have certainly seen obstinate sores in the leg cured by small and repeated bleedings. Dr. Chapman arrives at the same conclusion, although by a different train of reasoning; he states that the blood-vessels and absorbents[255] are to a certain extent “antagonising powers:” instructed by this obvious fact, we ought, says he, in the exhibition of diuretics to regulate the state of the system by interposing purgatives, or even venesection, as the state of the circulation may indicate.

EMETICS also, in certain conditions of the system, would appear to render the stomach more sensible to the impression of other remedies; Dr. Eberle, of Philadelphia,[256] has remarked such an effect with respect to the administration of the Peruvian Bark.

CHANGE OF DIET AND OF HABITS may be also classed amongst the _Ajuvantia_, but the young practitioner must be warned that he is not to exercise his _Caduceus_ as Sancho’s Doctor did his wand. I have seen a young disciple of Esculapius so vex his patient, that his food became more nauseous to him than his medicine, and I verily believe his Physician was more irksome than his disease. It was well observed by Dr. Percival that the prejudices of the sick should never be contemned with wantonness, or opposed with harshness; for, silenced by authority, they will operate secretly and forcibly on the mind, creating fear, anxiety, and watchfulness. And with regard to diet it may be here stated, that no function of the body is so materially influenced by mental impressions as that series of actions constituting what is termed _Digestion_—the unexpected communication of any distressing event destroys the keenest appetite,[257] and converts the sensation of hunger into one of disgust at the bare idea of food: a fact which did not escape the penetrating eye of our immortal Shakespeare, for he represents Henry dismissing Wolsey from his government with these words—

—— Read o’er this;
And after, this: and then to breakfast
_with what appetite_ you have.

If feelings of disgust are excited by the repast, the stomach will never act with healthy energy on the ingesta; and in cases of extreme aversion, they are either returned, or they pass through the alimentary canal almost unchanged: on the other hand, the gratification which attends a favourite meal is in itself a specific stimulus to the organs of digestion, especially in weak and debilitated habits. Dr. Merriman has lately communicated to me a case which affords a striking illustration of the powerful influence of the mind upon these organs: a lady of rank labouring under menorrhagia, suffered with that irritable and unrelenting state of stomach which so commonly attends that disease, and to such a degree that every kind of aliment and medicine was alike rejected: after the total failure of the usual expedients to appease the stomach and procure relief, she applied to Miss Prescott, and was _magnetised_, when she immediately, to the astonishment of all her friends, ate a beef steak, and continued to repeat the meal every day for six weeks, without the least inconvenience! but the disease itself, notwithstanding this treacherous amnesty of the stomach, continued with unabated violence, and shortly afterwards terminated her life.

The diet of a sick person ought never to _combine too much nutriment in too small a space_;[258] when so given it will even in health be followed by _fermentation_ instead of _digestion_; and although we may admit the expediency of that domestic maxim, “_a little and often_,” yet this is to be received with limitation; no one, for instance, who possesses any philosophical knowledge, will adapt his practice to the notions of Sir William Temple, who asserted that “the stomach of a valetudinarian was like a school-boy, always doing mischief when unemployed,” and that we should therefore not allow it any interval of repose: to this I answer, that the conversion of aliment into blood is effected by a series of elaborate processes, several of which are only perfectly performed during the quiescence of the rest: it would seem, for instance, that the process of _chylification_ is incompatible with that by which the first changes are produced in the stomach; this is evident from the well-known fact, that our appetite for food ceases when the former process commences, although the repast should, at the time, have been insufficient to satisfy the craving of nature; whereas, in diseases of imperfect, or depraved digestion, as in _Diabetes_, _Tabes Mesenterica_, &c. we find that the appetite for food is never satisfied by the most nutritive meals. It merits notice also, that whenever the stomach be called into action during the assimilating stages of digestion, the process will, in weak persons, be much disturbed, if not entirely suspended. These views have long since confirmed me in the propriety of treating mesenteric affections in a manner very different from that which is generally pursued; and I may add that the result has been very satisfactory. The plan to which I allude, consists in enforcing longer intervals between each meal, which should be scanty, and in quantity short of what the appetite may require; in this way are the unwilling absorbents induced to perform their duties with greater promptitude and activity; but it is a practice which, from the extreme anxiety of friends and relatives, the feelings of craving and hunger expressed by the patient, and the mistaken but universal prejudice respecting diet, it is always painful to propose, and generally impossible to enforce; where, however, circumstances have given a full and unreserved controul, the advantage of the plan has been most decisive.

There is still another remark which I am desirous of offering, in this place, on the subject of Diet; _viz._—that in all cases of feeble or imperfect digestion, _the Valetudinarian ought never to take his principal meal in a state of fatigue_—and yet let me ask, whether there is a habit more generally pursued, or more tenaciously defended? Aye, and defended too upon _principle_—the invalid merchant, the banker, the attorney, the government clerk, are all impressed with the same belief, that after the sedentary occupations of the day, to walk several miles to their villas, or to fatigue themselves with exercise before their dinner, or rather early supper, will sharpen their tardy stomachs, and invigorate their feeble organs of digestion. The consequence is obvious,—instead of curing, such a practice is calculated to perpetuate, and even to aggravate the malady under which they suffer; by calling upon the powers of digestion at a period, when the body is in a state of exhaustion from fatigue. Often have I, in the course of my practice in this town, cured the Dyspeptic invalid, by merely inducing him to abandon so mischievous a habit.

II.
TO CORRECT THE OPERATION OF THE BASIS, BY OBVIATING ANY UNPLEASANT
EFFECTS IT MIGHT BE LIKELY TO OCCASION, AND WHICH WOULD PERVERT ITS
INTENDED ACTION, AND DEFEAT THE OBJECTS OF ITS EXHIBITION.

A. _By_ MECHANICALLY _separating, or_ CHEMICALLY _neutralizing, the offending Ingredient_.

The scientific physician, from his knowledge of the chemical composition of a medicine, and of the principles upon which its different qualities depend, is enabled to remove or render inert the element which imparts to it a deleterious operation; thus it has been found that the peculiar principle in the _Spanish Fly_, which so frequently irritates the urinary organs, is soluble in boiling water; ebullition in water therefore offers the means of depriving it of the power of thus acting upon the kidneys, while it does not effect any alteration in its vesicatory properties. It is upon the same principle that many vegetable substances of a very acrid nature, become harmless by boiling, or by chemical manipulation, and some of them might even in times of scarcity and want, be introduced as wholesome and nutritious articles of diet. The experiments of _Westring_ shew that the bitterness of the _Lichen Islandicus_ may be entirely removed by maceration in an alkaline ley, and a tasteless, but highly nutritious fecula be thus obtained; in the same manner the _Æsculus Hippocastanum_ (Horse Chesnut) may be deprived of its bitterness, leaving a residuum which will afford a kind of bread; and according to _Parmentier_ (_Recherches sur les vegetaux nourissans_,) excellent starch may be also made from it. _Dr. Darwin_ observes, that if the roots of _White Bryony_ be rasped into cold water, and agitated with it, the acrid juice of the root along with the mucilage will be dissolved, or swim in the water; while a starch perfectly wholesome and nutritious will subside, and may be advantageously used as food; by a similar species of address the French prepare from the acrid _Arum_ the harmless, but highly prized cosmetic, called _Cyprus powder_.

There are many substances which receive a much pleasanter mode of operation by having their solubilities increased or diminished; thus the griping occasioned by several drastic purgatives is obviated by the addition of some alkali: and the nauseating tendency of _Camboge_, which arises from its too easy solubility, is prevented by incorporating it with some insoluble body; as in the _Pilulæ Cambogiæ Comp:_ but the farther consideration of this question will be resumed in the fourth section of the Analysis. (iv. c.)

Numerous attempts have been made to correct the inconvenient effects of _Opium_, such as nausea, head-ache, and costiveness, by removing the resinous element, upon which such evils have been supposed to depend, and we have accordingly been at different times presented with a variety of _Formulæ_ for the accomplishment of so desirable an object; (_see Opium_). More recently, opium has been discovered to possess _two_ active principles, viz. _Morphia_ and _Narcotine_, which would appear from the researches of M. Majendie to exert very different powers upon the animal system; the former imparting to opium its _soporific_, the latter, its _exciting_ property; whence it is proposed to remove this latter principle in order to render the operation of opium milder, and at the same time to divest it of those objectionable properties which so greatly limit its medicinal utility. _See Opium._

B. _By adding some substance capable of guarding the stomach, or system, against its deleterious effects._