Practical observations on the action of morbid sympathies : as included in the pathology of certain diseases; in a series of letters to his son, on his leaving the University of Edinburgh, in the year 1809

Preface

Tue following Letters were originally written for the use of the Author’s Son, at the time of his leaving the University. The considerations which have led to their publication it is unnecessary to explain ; it is sufficient to say, that, conscious as he himself is of the correctness of the principles which they exhibit, they having been gradually assumed in the course of many years of medical practice, he is not without hopes, that, to young men, their perusal may be useful, by helping to assist them in distinguishing with correctness many varied shades of morbid phenomena, which might otherwise es-

Vl PREFACE.

cape the eye of transient notice ; and to experienced practitioners, whose medical opinions have been long established, he is desirous only of offering them as subjects of candid reflection.

Contents

LETTER L

Dear ConsipEriNc that correct views of Diagnostic Pathology are of such essential importance for the acquirement of that knowledge in your profession, which isin-. dispensably requisite, in order to qualify you for exercising its various duties with precision and comfort to yourself, as well as with that justice which is due from you to those who may commit their health to your care, it necessarily becomes an ob-

ject of your most sedulous study. It com-

LETTER II. Dear

Wuen the healthy operation of any organ of the body is interrupted by an injury received either in its structure, or in the moving power, there necessarily occurs some imperfection in the action of that department of the system wherein the diseased organ is destined to perform a part. This interruption, as wellasits cause, is sometimes cognizable by the senses, but it also very often happens, that both the one and the other lie so far concealed, that, while it is evident a disease somewhere exists, yet its nature, as well as the _ seat of the defect, is only to be guessed at by the aid of observation and of certain signs.

A

In investigating the true seats and causes of many of the morbid phenomena, the operation of the generallaws of sympathy inherent in the nervous system forms an important field of observation ; and although their study has been but little introduced into pathological reasoning, yet be assured that the subject merits the most serious attention from the practical physician, numerous being the errors, or rather the misconceptions, which daily occur from mistaking what is only the sign or effect of an existing cause, for the essence of the disease itself Many and various are the cases of morbid sympathy induced in the mass of disease, to_ which the human body is subject, and not a few of these are of so important and formidable a nature, as to constitute, in fact, some of the most painful forms of human distress ; for which reason I wish to point them out to your notice, as objects deserving your peculiar attention and study. I have’ remarked to you in the preceding letter, that one material reason for that uncertainty which remains suspended over diagnostic pathology, is derived from the want of fixed data, or such ascertained principles, as by fair reasoning should lead to correct inferences; I have also observed, that, where such dizect demonstration is unattainable, recourse must be had to those sources of opinion which may approach nearest to it. |

It is unnecessary for me to go over those grounds upon which I have founded the views I am now presenting to ‘you; it is enough to say, that professional attentions have led me to think, that, in the general law of sympathy, principles are very evident, which approach so nearly to axioms, that in practice they may be very justly acted on with confidence.

‘The brain, and its appendages of © nerves, being that medium through which the living principle acts upon the otherwise inert organic structure ; as also the medium through which the mind is made conscious of injurious applications offered to any part of the machine. It may properly be said, that every part of the human body is capable of sympathising with the rest; because we see, that no ‘part of it can admit of having the sense of feeling excited to the height of pain, without the whole frame also suffering an uneasy sensation. But there are likewise parts or organs which are more intimately connected with, and dependent on each other, than upon the rest of the body, constituting a specific or peculiar sympathetic affection. Some of these phenomena are so common, as to be noticed merely as things of course ; as, for instance, when a person is affected with head-ache, a disordered state of the stomach is at once remarked as the cause of B this, in consequence of experience having frequently shewn it to be so, affecting some membranous part of the craneum by sympathy. Ifa pregnant woman has nausea and vomiting, irritation in the uterus, for a similar reason, is immediately admitted as the cause of it affecting the stomach by sympathy also ; and they are readily passed over as peculiar facts, without reflecting that they are in reality instances of the exertion of a general law, which may be called into action in numberless other occasions’ as well as in these. It is that law of the sentient nervous system, whereby, upon certain modes of irritation being occasionally applied to some particular parts of the body, morbid sensations and morbid actions will be excited in some distant organ, and is therefore very properly designed morbid sympathy.

Morbid sympathetic impressions are sometimes attended with pain, and some-

, times not ; in which last case, the original irritation gives only, either an increased exertion of the natural office of the sympathising organ ; or else its natural and healthy action is thereby impaired, and even sometimes totally suspended. The first is exemplified in the vascular system, when it is excited to fever by acrimonious irritation in the alimentary canal; or by the increased secretions which take place in the liver and other abdominal glands, as also in the salivary gland, from the same cause. - The second is illustrated by the power of the heart, and the whole vascular system being reduced below its natural standard ; exhibited in palpitations, languid pulse, torpors of the limbs, syncope, and even death itself, in consequence of the mere application of a peculiarly offensive substance to the nerves of the digestive organs. |

At other times, the pain attending morbid sympathy is very great, and this will greatly depend on the natural sensibility of the part or organ so affected. The most common source of sympathetic pain, seems to arise from the impression being seated, in form of spasm, on a muscular part, a portion of a muscle, or on a fibrous membrane. It appears also occasionally to occupy a nervous chord, a plexus of nerves, or a ganglion ; on which occasions the attending pain is necessarily very great. But as the medullary part of the nervous structure is possessed of no contractility, therefore, if it is supposable that a sympathetic affection is ever exclusively seated on that part of the chord, it is to be presumed that the attending pain may arise from a morbid excitement: of its natural sentient principle. But although the nervous medulla has in itself no contractility, yet its mempbraneous sheaths are possessed of muscular fibrillae, and blood vessels like other membranes, and therefore may be affected with sympathetic spasm, so as to influence the medullary part with painful sensations. There is reason to believe that this in fact occurs.

The natural healthy operations of muscular action, even the most severe voluntary exertions, are performed without the smallest sensation of local pain ; but when excited to involuntary spasm by some irritating morbid cause within the body, as in convulsive diseases, the attending pain becomes very severe, often excruciating. But that state of a muscle which is denominated spasm, is nothing else than an excessive exertion of its natural contractile power, to which it is capable of being excited by morbid irritation, applied either directly to the muscle itself, or indirectly by an action of morbid sym- _ pathy, arising from irritation applied to a distant part of the nervous system. Wherever, therefore, muscular fibres exist, morbid spasm may also exist; consequently, not only the fibres of large muscles, but the smallest fibrous threads of all the membraneous parts, are also susceptible of spasm from irritation, applied either directly or indirectly from — morbid sympathy; and hence, spasm, when fixed in the fibres of a membrane by sympathetic affinity, may be productive of painful sensations, as naturally as when seated in the fibres of a large muscle. vbr It is farther to be observed, that although the most violent spasms of large muscles are seldom, if ever, succeeded by local inflammation, as is instanced in epilepsy, hysteria, &c., yet when the muscular texture of a membrane becomes the seat of a sympathetic spasm, local inflammation of that membrane is speedily induced, the coats of its capillary vessels being probably also soon included in the sympathetic influence. Give your particular attention to this circumstance, because, from this fact, that inflammation in a membrane speedily follows, as the consequence of sympathetic spasm formed in it, certain important phenomena in the pathology of inflammatory diseases are derived. Instances of this frequently occur in spasm of the -instestines, and are often exhibited to the eye-sight in periodical headache, more especially if the periodical sympathetic pain extends to the membranes of the eye. I have in that case observed the adnata become regularly inflamed during the continuance of the fit, disappearing gradually in time of the intermission, and returning again with the returning paroxysm ; at other times, on such occasions, the inflammation is more permanent, and establishes a most distressing form of ophthalmia.

Here then we have a certain ah i of pathological facts, which must be ad-

D4 mitted as data to be reasoned from, because their existence is demonstrably true, and I believe are as certainly so as any axiom in geometry.—1st, Irritation applied to certain parts of the body, can excite painful sensations, and morbid action in a distant organ, by the operation of the law of sympathy inherent in the nervous system ; this frequently occurring while the mind remains unconscious of any uneasy feelings at the place where the irritation is applied. 2d, Morbid sympathies are sometimes attended with pain, and sometimes not. In the lat- . ter case, the morbid effect consists either merely of an augmented action of the natural powers of the sympathising organ, or else, as happens at other times, the natural healthy powers of the organ are thereby impaired. But when an action of morbid sympathy rises to the height of exciting involuntary spasm in a muscle, in a portion of a muscle, or in the fibrous texture of a membrane, it is uniformly attended with more or less of painful sensations in the sympathizing organ, andthere, occasionally, ina severe degree. 3d, When a membrane is the seat of sympathetic spasm, the circulation in that membrane is frequently influenced in such a manner as speedily to produce inflammation, more especially in those of a firm texture. In contemplating the exhibition of morbid sympathies, you must take notice, that they vary much in their form and appearances ; that the original irritating cause will at one time produce a single peculiar sympathy only; and at another time will give a number of sympathizing affections, occupying seve- - ral organs of the body at the same time, and all of these appearing to flow from _ the same source; as, for instance, the many forms of uneasy sensation which can be traced, as resulting at one and the same time from vitiated fluids contained in the stomach.

Upon other occasions, the effects of the primary cause are progressive, and the first sympathetic affection will produce a second depending upon it, and this again will give a third in like manner ; and so on in a series of morbid sympathies flowing in succession from each other, and exhibiting morbid appearances peculiar to the organs included in the climax. This is demonstrated when irritation is excited in the kidnies or bladder by a stone or gravel; or in the uterus in some forms of hysteria, and in the case of pregnant women; which organs have a peculiar sympathetic affinity with the stomach and intestines. But the stomach again readily communicates its morbid influence to the head; and there, if the morbid sympathy shall be seated within the cranium, there is no organ or function which may not be included in the circle; the whole phenomena at the same time depending on the primary irritation subsisting in the urmary organs or uterus.—And further, you must observe, that the painful sympathetic spasm very often shifts its seat ; which appears to be the effect of some unperceived natural cause; or, as sometimes happens, from the agency of a medical application made to the parts. But the original cause of irritation still remaining in action, the effect of that cause merely changes its place to some other organ, which may stand next in rank of affinity to the primary cause, and soon to a third perhaps, or even return to the first, as circumstances attending the original cause may determine; but this will appear more for~ cibly to you, in considering the sympathetic phenomena of certain diseases af- _terwards. With regard to the vinculum, connecting the sympathising part with that where the irritation is applied, we remain totally in the dark; all that we have in our power, on this point, is to observe, and by careful observation to mark, demonstrable facts ; and these, by candid induction, ought to lead to correct practice. Neither is it known whether the communication of sympathies be direct, being established by the various subdivisions of the nervous chords, or if their communications are circuitous, always passing first to the brain, and so by the medium of the sensorium commune exhibiting these phenomena which appear in the sympathising organs. The late Dr White of Edinburgh, in his excellent work on nervous diseases, 1s of the latter opinion; at the same time it appears most probable that both of these modes of action may occasionally exist.

Il am, &c.

Letter III

Dear — _ Arrer having made the above obser-. vations, I will next proceed to make some remarks on such morbid sympa~- thies as are conspicuous, either in the course of certain particular diseases, or which, at other times, form the principal phenomena of the diseases themselves. That extensive and varying influence which a healthy or diseased state of the digestive organs, and of the stomach in particular, exercises over the whole hu- _ man frame, both of body and mind, has long been the observation of pathologists, and of course it constitutes an object of the deepest importance to the physician, to become well acquainted with the extent to which this influence reaches, as well as the laws by which it is governed ; in order that he may thereby be enabled to correct the operation of these laws, when they are called into action in a manner inconsistent with health.

When we take into consideration the extensive surface furnished with innumerable papille, that is, the extremities of sentient. nerves, which the stomach and intestinal canal constantly present to the variety of irritating matters which is daily poured into them from the combined sources of extraneous articles of food, and the occasional morbidity of their natural secretions, it is no way surprising that, the primee viee are observed to be that part of the system where we meet most frequently with these primary irritations which are productive of the diseased appearances alluded to. The morbid sympathies which subsist betwixt ‘the stomach and certain distant parts are no doubt reciprocal; but it is observable, that the sympathetic affinity in these parts, flowing from irritation in the stomach, &c. are far stronger and more direct than those which affect the stomach from a distant origin. Upon the whole, however, the great object in practice is not so much to determine the specific form of the sympathetic affection, as to decide whether the morbid phenomenon presenting itself is really sympathetic, depending upon affinity with irritation in some distant part ; or whether it be idiopathic, and the effect of a primary local derangement in the organ where the pain or uneasy sensations are seated; or whether it proceed trom both of these causes acting together. It is further to be noticed, that, in contemplating the pathology of sympathetic diseases, the various idiosyncrasies of con- ‘stitution, whereby an individual may become violently influenced by particular irritating causes, which, if applied to another, or to a hundred others, would produce little, or perhaps no effect whatever, constitute a fact of the most important consideration in explaining many of their phenomena.

I wish you again to remark, that although spasm in the large muscles, or in a portion of the fibres of large muscles, be not followed with any inflammatory affection, or a febrile state arising from that cause, yet when the sympathetic spasm takes place in membranes lining cavities, or on membranous ligaments, as the membrane of the fauces, the trachea, and bronche of the lungs ; the pleura or peritoneum, or coats of the intestines, and membranes surrounding the glands ; as also the ligaments of the joints, and tendinous appaneuroses, inflammation on the part is yery frequently the consequence; and in consequence of this local inflammation drawing the whole vascular system and heart into increased action by morbid sympathy, a febrile state is produced. But spasm does not appear to operate aS a direct cause of pyrexia of itself, till it has in the first place induced local inflammation. It is therefore probable that the stricture on the skin, which accompanies feverish paroxysm, is no cause of fever, but merely a morbid sympathy depending on irritation, applied to some distant part of the body, most commonly within the intestinal canal; and, moreover, it is often observed to exist without a quickened circulation. On the other hand, from the affinity which subsists betwixt the surface of the body and the intestinal canal, as well as the glandular system connected with it, it so happens, that when the general perspiration is checked by some external occasional cause, as, for instance, by the application of cold, the natural secretions into the cavity of that canal are all increased, C

S4 which secretions, when permitted to remain there, so as to become acrid, re-act again upon the system, and become the cause ‘of disease.

Having premised thus far respecting the general laws of morbid sympathy, I will now go on to offer to your attention some observations on the operation of these laws, as exhibited in the phenomena of certain diseases; and here I wish to remark to you once for all, that with regard to.the practical use of systems of nosology, notwithstanding the ‘specious hope of utility in diagnostic pathology, which classification holds out, it has not in reality proved materially useful in that department of medical science. ‘The reason is, that what are styled definitions of diseases, communicate little more than an enumeration of certain phenomena which mark a departure from health, and the causes of which remain afterwards to be discovered, in place of being what, if possible, it certainly ought to be made, a climax of circumstances ; which, step by step, shall open to your view the complete fabric of disease, directing you to its source. You will therefore find, that nosological arrangements are all artificial structures ; whereas the phenomena of morbid sympathies, in so far as they form the origin of disease, are all the operation of naturak causes, and are very generally to be traced to their primary sources of action ; and, upon the whole, you will see that nosological classification is as yet very deficient, and, as it now stands, may be a most useful statement for the purposes of a public teacher, but is entirely useless, in diagnostic pathology, to a practitioner. ‘This defect ensues from the difficulty which occurs in ascertaining with precision to which class, order, and genus, the particular instance of disease which you are investigating ought to be referred.

I shall therefore, in what I mean to say to you, pass from the form of nosological method, and merely detail what long experience has pointed out to my understanding as the only tenable ground on which the nature of a numerous class of diseases appears to be intelligible ; in fact, the operations of the laws of sympathy, through the nervous influence on the living system, is a thing demonstrable to the senses; and any theories which I have ventured to offer on their pathology, are very nearly as much so, to an unbiassed mind. At least this J will assert for myself, that to my conception they approach far nearer to the certainty of demonstration, than any other pathology I have met with on the same subjects, and have served to direct | my own practice, in a satisfactory manner, through a mist of insulated facts and general assertions ; while every additional year’s experience has served more and more to strengthen my opinions. | |

Thinking it unnecessary to enter on a statement of the various hypotheses which the history of medicine has presented, I wish exclusively to direct your attention to the study and consideration of some morbid appearances which seem directly to arise from the action of certain laws of the animal economy that are decidedly known to exist; as also to the endeavour to trace the connection betwixt the effects of the action of these laws, and the morbid causes from which these effects proceed. Indeed, the time is mis-spent which is employed in ex-~ plaining the doctrine of disease on a preconceived theory, or in trying to form a theory for the purpose of explaining the nature of a disease, in place of observing impartially the phenomena of its progress, and of trying to penetrate into the nature of its causes, with the hope of adopting a rational practice for. its removal.

A febrile state of the body is perhaps the most frequent of all diseases, and has at all times justly met the highest degree of consideration. In attending to the descriptions and definitions which have been delivered of it, you will readily see that they are often diffuse, and by no means expressive of a clear concise idea, but consist of the enumeration of a list of certain morbid appearances ; and that by simple fever is implied a supposed ideal something within the body, acting as an abstract principle, independent of any topical affection, but attended by a train of circumstances peculiar to itself as its effects ; such as sensation of cold, succeeded by heat, thirst, quick pulse, prostration of strength, with the - impaired action of other functions, &c. That vicissitudes of cold and heat, with thirst, quick pulse, &c. are concomitants of a febrile state, is certain; but I believe the truth to be, that no such abstract principle as the above can be demonstrated to exist, and that a febrile state of the body is at all times the result of some primary cause applied to, and exciting to morbid action the moving powers of the system. If you will consider every account which has been given respecting the attending phenomena of a febrile state, you will directly discover that there is one only of these symptoms which invariably occurs, and which is always present from beginning to end, viz. an increased action of the heart and arteries. ‘This circumstance is one which forms a sine qua non in fever, seeing all the other circumstances included in the description of pyrexia may also exist without, and independent of, a quickened circulation, and of course do not of themselves necessarily exhibit a febrile state of the body. You will at the same time remark, that the merely accelerated circulation of the fluids, which is the result. of voluntary muscular motion alone, is not a state of pyrexia; this last being always understood to be the effect of peculiar causes internally applied to the moving principle of the machine.

That department of the machine, then, to which such exciting causes are applied, and through which these morbid appearances are exhibited, as well as the laws of its action, come naturally to be points of interesting deliberation, in reflecting upon this important disease.

Tam yours, &c.

LETTER IV. Dear

[I am very solicitous to impress the following view of febrile diseases on your notice, as Meriting your careful attention. I wish you to compare it with what you have read on the subject ; and if it shall prove useful to you in rendering your ideas of fever less complex, they will in proportion become more clear, and will enable you to proceed with greater firmness and decision in practice.

You will remember then, that a febrile state, or a permanent increased action of the heart and arteries, may be derived either from irritation applied to the nerves of some distant part of the body, between which and the vascular system a primary affinity subsists, exciting that’ system into violent action by morbid sympathy ; or from the effects of something of an irritating nature having been received into, and circulating with the blood, and thereby directly applied to the internal surface of the heart and blood vessels themselves. But the establishment of a febrile state of the system, as derived from remote causes within the body, appears very demonstrably to acknowledge the following primary distinctions : 1st, As derived from the effects of acrid matter applied to some department of the nervous system, and exciting a morbid action of the heart and arteries by morbid sympathy ; but such a remote cause, experience shows, is most commonly seated in the digestive organ. _ 9d, As derived from the effects of irritation, arising from organic obstruction, somewhere existing in the body, and exciting increased action of the heart and arteries, by morbid sympathy.

3d, As derived from the effects of something of an irritating nature received into, and circulating with the blood ; being thereby directly applied to the internal surface of the heart and arteries. ~ 4th, As derived from passions of the mind, exciting an increased action of the vascular system, by morbid sympathy. |

5th, As derived from two or more of these primary causes of on acting at the same time.

Although any one of these causes, when applied alone, may of itself be productive of pyrexia ; yet it very frequently happens, that in consequence of certain occasional derangements occurring in the body by the operation of the first cause which is applied, one or more of the others are observed to come early into action at the same time; thereby forming a supervening or accessary cause of fever. The first of the above-mentioned primary causes, viz. Irritating matter applied to the nerves of the stomach and intestines, is the source of many morbid phenomena in the animal economy, as well as those of fever. But what the exciting circumstances are which determine one part of the body to be occasionally more amenable to this cause than another, is totally unknown ; only we are certain that it is so; and that from irritation in the prime vie, the vascular system in one person shall be excited into violent action, while the muscles are remaining free from any inordinate influence. But in another person, irritation in the same organ shall be productive of violent muscular spasm, or perhaps painful sensations in some dis- - tant part of the body, while the artereous system remains undisturbed. a It is the first of these phenomena,—the effects of irritation in the primee viee upon the vascular system, exciting it into violent action by morbid sympathy, and as forming the primary cause of a febrile state, which I mean here to take notice of. It is one which I believe to be the most common, as well as the least complex form of fever. It is the least complex, because it most frequently depends on one uncombined cause; on which account it comes very properly to be first considered, and is best distinguished by the appellation of gastric fever. The pathology then, and attending morbid sympathies of gastric fever, I conceive to stand thus :

In consequence of certain acrimonious matter being applied to the nerves of the | inner coat of the stomach and intestines, a sympathetic affinity takes place betwixt that organ and the vascular system, where- _ by the natural action of the heart and arteries is accelerated, and the velocity of the circulation is of course increased.

This, in the next place, is succeeded by a train of uneasy sensations resulting from the excessive action of these vessels, and a velocity in the current of the blood beyond what is consistent with health.

During a certain period of time previous to the establishment of this febrile state, a degree of departure from a healthy state of the primze vie may always be remarked ; such as impaired appetite for food, weight at the precordia and abdominal distention, thirst, parched mouth, and furred tongue; to these are commonly added, signs of impaired and irregular action of the nervous system in general, arising from morbid sympathies with the same source in the prime vie ; such as languor, disturbed sleep, headache, dry skin, vicissitudes of heat and cold, &c., till at last the contents of the alimentary canal having increased in acrimony, @, €. in irritating power, a feverish paroxysm is formed, accompanied with

4° an ageravation of all the former complaints, together with augmented heat of the whole body. |