COMMENTARY X.

METASTASIS, SYMPATHY, AND CONVERSION.

THE disorders hitherto treated of are of a fixed and tangible character, and in which there is a visible disturbance both of the mental and corporeal functions. But there are many other disorders where the characters are changeable, and which produce mental derangement, but in an indirect and more mysterious manner. Diseases of remote parts frequently occasion mental derangement by shifting morbid actions to the brain.

There are three modes through which the brain is morbidly affected by remote diseases, and insanity is induced. 1. By metastasis, or translation;

2. By sympathy;

3. By conversion.

These three modes of originating mental derangements have hitherto been usually considered as one and the same, under the designation of sympathetic causes, and hence some confusion has arisen; but in fact, they are distinct morbid actions.

In metastasis, the part or texture primarily affected is completely freed when the morbid action originating in that part removes itself to another; but the morbid action may return again to its original seat, and leave the part secondarily affected free.

In sympathy, the functions of an organ or part primarily deranged may remain permanently so, while those of a remote organ or part shall assume all the characters of the morbid action of the primary affection.

In conversion, a disease shall leave a part or texture

where it was situated, and another disease in some other part or texture is immediately superinduced.

1. Metastasis.

Although every disease by metastasis or translation be a secondary affection, yet it differs widely, as may be seen in their respective definitions, from secondary or sympathetic affections.

Thus, a metastatic affection may quit the organ or part to which it is translated, and return to that primarily attacked, and there run its course: a sympathetic affection is produced from a lesion of structure or function of a remote organ or part, which organ or part is not freed by the secondary morbid action it has raised; but both the primary and secondary morbid actions may proceed together.

Metastasis, therefore, is a simple translation of a morbid action from one part to another: sympathy excites a corresponding morbid action in another part, which may act synchronously or alternately; and this action may persist, while the part primarily organically lesed may recover and be restored to its natural functions.

There is yet another difference between metastasis and sympathy: the one arises from, and when transferred, originates, an acute affection, or what may be termed super-excitation; the other generally originates an affection of a more chronic kind, characteristic of sub-excitation. Both these morbid conditions, however, appear to be disorders of the circulation, inducing local determinations, either in the arterial or venous systems, and are probably propagated by the communications of the nervous ganglia.

Metastasis and conversion may be designated vicarious affections, where one disease is transferred and acts for another. They are different modifications only of one common action, the causes of which may be properly denominated masked; for there is no indication, perhaps,

of the event till it has occurred; and it often does occur without the possibility of prevention, even if it be suspected. Insanity arising through any of these modes demands peculiar consideration; for as they are all secondary, and not primary, affections, so will the manner of treatment and the prognosis differ.

The effect of a translated morbid action will be correspondent with the part attacked: hence there is no agreement between the degree of the old and the new excitement. That which produces but a slight impression in one part, when translated to another excites a violent commotion. Many inflammatory diseases are susceptible of translation. Thus gout, which, when confined to the extremities, is a local complaint, occasioning comparatively little constitutional, and rarely any mental disturbance, produces by metastasis to the stomach high inflammatory action, and when to the brain, cephalitis, pyrexia, and furious delirium. The same occurs in acute rheumatism; but the translation in this case is usually to the heart, and not to the stomach; but if to the brain, whither I have known it shift, it creates all the symptoms of acute inflammation of that organ.

Now all morbid actions, perhaps, are susceptible of different modifications, and when transferred to the brain, occasion different degrees and forms of delirium. The importance, therefore, of studying them, and distinguishing the phenomena of metastasis, sympathy, and conversion, in relation to mental derangement, is obvious.

The morbid action of organic diseases is often suddenly transferred to the brain, and occasions while it lasts a real delirium, to the complete suspension of the original disease; and the patient, from the last extremity of existence, becomes suddenly endowed with a degree of muscular power truly amazing. In this condition all the phenomena of insanity are developed. It may be continued for months; and upon the sudden subsidence

of the delirium, the original disease resumes its course, and the patient dies in a few hours or days. This frequently occurs in pulmonary consumption.

Aretaus notices the propensity in phthisis to induce insanity; and Mead has observed, that there appears an interchangeable relation between lunacy and phthisis pulmonalis; the latter being cured by the accession of the former, and recurring as soon as the brain resumes its natural functions.

In the last stage of consumption, a delirium is apt to come on; and I have several times been called to visit a patient in this state, from an impression in his own opinion that he was insane. But I have invariably found this symptom a certain indication of approaching death.

Not only every viscus, but the mucous membranes likewise, which are so much more liable to stimulation, possess the power, and transfer morbid actions more frequently, perhaps, and with greater facility, than the

viscera.

I have remarked, that when the brain, is affected by metastasis from a remote diseased organ, the degree of mania or delirium, though perhaps violent, is of a more simple character than when transferred from inflamed membranes.

Numerous diseases have an aptitude to shift to the brain, of which we cannot be too much on our guard. Besides phthisis, asthma, chronic catarrh, gout, rheumatism, and all cutaneous eruptions, are in this way causes of insanity. The sudden suppression of the menses, and of hæmorrhages from the lungs, nose, or hæmorrhoidal vessels; or of habitual discharges from old ulcers, setons, issues, chronic diarrhoea, &c., transfer irritation to the brain. The return of such diseases to their proper seats, the re-appearance of eruption on the skin, or the renewal of the suppressed discharges, are the

natural and ordinary means of restoring sanity of mind in such cases.

The following is a fatal case of the transfer of inflammatory action:

A young man, rather addicted to the drinking of spirits, was seized with all the usual symptoms of quinsy. He was recovering, when, the first day of his having liberty to go down stairs, he found means to indulge in his propensity for strong liquor. There was reason to believe he took only a small quantity; but he was in a few hours after attacked by fever and furious delirium, and all the symptoms of true cephalitis. The surgeon who attended him resorted to such judicious measures as the great excitement seemed to demand, and with a favourable effect. The family, however, alarmed at the vigour of his practice, suggested a consultation; the result of which was a cessation of proper remedies, and the adoption of such as were suitable to simple mania.

On the following day, the patient being worse, I was called in, under the conviction that it was only a maniacal attack. It was too late effusion had evidently taken place, coma supervened, and he died in about ten hours.

Insanity may be induced by suppressing recent diarrhoea of which the following is an example:

A young healthy man, aged twenty-four, was attacked with rigors and fever the 29th of November, and a smart diarrhoea followed. There was at the time in the house a fatal typhus fever, with which he believed he was infected.

Finding that he did not get better, he set off on the 3d of December from Cheltenham for his native village, near London, travelling all night. Though strongly urged, he had suppressed all evacuation, and had scarcely taken any nourishment during his journey.

He arrived next morning very exhausted, and soon