There is, very rarely, any considerable effect produced on the arterial system by iodine, if it be given with propriety and caution. Sometimes it accelerates the pulse in a slight degree; it frequently occasions a little mucous expectoration from the chest, and it often raises nervous symptoms in delicate subjects, which are very distressing. I saw it given to a young woman in one of the public hospitals in Paris, in whom it produced such a state of insomnia that she told me she had not slept at all for a whole week, though she had been a very good sleeper before. I have said that it affects the pulse but a little, yet it sometimes stimulates very powerfully the arterial vessels of the tumor. This is mentioned by all the authors who have written on iodine, and is one of the most singular circumstances in its medical history!
This irritation of arterial vessels frequently becomes active inflammation, requiring the use of bloodletting for its relief. Topical bleeding will, in general, be found fully competent to remove it. Indeed, it sometimes happens that when the iodine has lighted up smart inflammation in the tumor, the arterial system generally is unaffected. To what is this effect on the vessels of the part to be attributed, from which the constitution generally is free?
The same is occasionally true of the absorbent vessels. I have seen some very large tumors discussed, while there was no evidence whatever of the absorbent vessels in other parts of the body having felt the influence of the medicine. It is a curious question, to determine by what law the constitution remains impassive to the action of a medicine, which affects remote and distant parts through the constitution. Certain tumors are of so irritable a nature, that a stimulus, which only serves to rouse the healthy energies of the body, excites the process of destruction in them. In the quaint language of a celebrated modern lecturer, “they are irritable beings, if you touch them they’ll kick.” But this is not the case with many of the tumors which are dissipated by iodine. Bronchocele, for instance, is of a slow growth; all the operations which go forward in its structure are of a very indolent and chronic kind. Such, also, is the case with the greater number of scrophulous tumors. Yet all of them have been dissipated, like a charm, by the agency of iodine.
In prescribing this medicine, it is very necessary not to lose sight of the effect I have just mentioned. When the tumor is very large, and especially in that kind of bronchocele, in which the principal enlargement of the thyroid gland takes place on its inner surface, where it is in contact with the trachea, the occurrence of inflammation is much to be apprehended. When a very large tumor becomes inflamed, the distress which it occasions, and the disturbance it excites in the constitution, are very considerable; and in the second case to which I have alluded, inflammation of the trachea is very readily excited.[5] Such cases are easily distinguished by the immovability of the tumor, and the effect they have in altering the voice. On dissection, the trachea is sometimes found to have been very much compressed by them.
It is now fit that I should mention the most common and beneficial methods of using this substance. Dr. Coindet has recommended the hydriodate of potass as an external application, and my experience has certainly confirmed his choice. The hydriodate of soda, however, will be found to answer equally well. Practitioners may choose between these two remedies. I have used the iodates, but I have found them at once more inert and more unmanageable. They possess all the virtues of iodine in a very remarkable degree, but they will be found to fail more frequently than the hydriodatic salts; and, if I may draw any conclusion from the few trials I have given them, they are more apt to excite disorder in the system. I have generally ordered half a dram of the hydriodate of potass to be united to an ounce and a half of axunge, and desired the patient to rub in a dram of this ointment over the surface of the tumor, night and morning. When the tumor is painful, it is not necessary to rub in. The ointment may be used in the manner recommended by Scattigna.[6] All that is necessary is to choose a portion of the surface of the body where the skin is very tender and thin, and simply to apply the ointment over night. For this purpose, almost any part of the body which is habitually covered may be chosen; but in the axilla, and in the inner surface of the thighs close to the scrotum, the absorption will be found most rapid.[7]
It is a more important question to determine the proper method of using this medicine internally. From my own experience, I am inclined to give a decided preference to the solution over the tincture. It is prepared by dissolving thirty grains of the hydriodate of potass in an ounce of distilled water. I have generally begun this preparation by a dose of ten drops, and augmented it gradually to twenty, and, very seldom, to twenty-five. This preparation can dissolve an additional dose of iodine; a formulary, however, to which I seldom, if ever, have recourse. I have found that the deleterious action of the medicine on the bowels was more marked, in proportion to the quantity of free iodine it contained. For this reason, also, I now seldom have recourse to the tincture, a form much used, because it is less expensive. Practitioners will, in general, find an advantage in confining themselves to the external use of iodine for the cure of bronchocele, and tumors, which do not arise from any vice in the constitution. In a few cases of bronchocele, however, it is necessary to have recourse to its internal use, especially when the disease exists in a strumous habit. By the use, either of the ointment, or of the solution in the way we have recommended, a soft bronchocele will be discussed in a month or six weeks. Those which are hard, and of old growth, generally take a little longer time, and many of these latter cases cannot be altogether reduced. I have seen two cases, however, in which the tumors gradually disappeared some weeks after the medicine had been altogether discontinued. Dr. Coindet says, that he has seen several cases of bronchocele, complicated with watery cysts, yield completely to the action of iodine. I have only had occasion to see one such case treated by this medicine. It was somewhat lessened in its bulk, and the patient was certainly relieved, but the disease was by no means cured.
If the iodine be given internally, it is indispensably necessary to watch its effects from day to day. No peculiarity of circumstances whatever can dispense the physician from this care; and if it be recollected that it is yet a new medicine, that unknown accidents, to which it is liable, may be discovered by future investigations, this caution will not appear superfluous. The case related by Dr. Coindet, to which we have already alluded at [page 36], in which a very powerful and painful effect was produced at the end of the fifth day, sufficiently evinces the necessity of the watchfulness here recommended.
When iodine acts kindly on the constitution, no other effect will be found to accompany its use, but a diminution of the tumor and a little nervous excitement, which is sometimes not so severe as to become disagreeable. The increase of appetite is a very frequent effect of iodine, and it is sometimes very troublesome, because it is extremely necessary not to indulge it. The diet of the patient should be good, but by no means full, which the occasional voraciousness of his appetite would lead him to adopt.
Having established that the use of iodine in bronchocele was owing to its effect on the absorbent system, it was natural to conclude that it would be of equal service in the cure of scrophula.[8] Accordingly, we find that Dr. Coindet made trial of it in the cure of the latter disease, soon after he had determined its virtues in the former, and that his experiment was followed by the most satisfactory result. I have already considered at so great length the general effects of iodine on the constitution, that little remains for me in this place but to mention the particular cases in which I have found it useful, and those in which it has failed my expectations.