MOXA, a word of uncertain origin, signifying any substance whose gradual combustion on or near the skin is used for the relief or cure of disease. This method was early practised in the East, particularly by the Chinese and Japanese, from whom it was copied by the Portuguese; but having fallen into disuse, it was revived by the French surgeons during the Egyptian campaign. The substance employed by the Chinese is formed of the downy covering of the leaves of the Artemisia Moxa (De Candolle) : but the down of many other plants, or the pith, may be used. The stalk containing the pith of the common sun flower (Ifelianthas annuas) is a very convenient means, when the prepared moxas cannot be procured. Those used in Britain are all imported from France, and generally consist either of a pyramidal or cylindrical roll of linen, which is mostly steeped in a solution of nitrate or chlorate of potass. The size of this is generally about eight lines high, and from four to five broad. It is ignited at the one end, and the combustion gradually extends to the other. This differs from the actual cautery by means of a red-hot iron, inasmuch as the latter pro duces immediately its maximum of effect, which progressively dimi nishes, while in the case of the moxa the heat gradually increases, and the greatest effect is produced towards the end of the operation. It is also different from a blister, both in its mode of action and in the stage of a disease in which it may be most advantageously applied. The general principles which should regulate the use of blisters having been already explained [BLISTER], as well as those connected with the actual cautery [EscrieRoncs], the following observations refer to the dis tinctive characteristics of the Moxa. We may remark that the pain is not so great as might be expected, indeed less than often attends blisters, and that it is often borne by females and children, or at least with the greatest fortitude.
Besides the secondary effects of the local application, which, being of a counter-irritative kind, are common to blisters and moxa, in the case of the latter there is the additional influence of a certain amount of caloric. "Caloric, applied under certain circumstances and with appropriate restrictions, stimulates in a powerful manner the capillary vessels, causing them to contract their diameters, and to circulate their blood with greater velocity ; and, either by this action on the capillaries, or by a direct one on the lymphatics of the part, it has also the power of exciting the function of the absorbents in a 'remarkable manner. The direct effects of moxa are seldom, if over, confined to the skin ; and if the moxa be applied through the medium of a needle, the calorie may be made to propagate its influence to any depth. The beneficial influence of mom, in relieving or curing disease, apparently depends on its tonic action over absorption and capillary circulation. Hence it should be employed in those cases only
in which there exists a state of debility of the capillaries and a con sequent retardation of their circulation, and a diminution of absorp tion ; and invariably avoided wherever there is increased action or active To hold the moxa over the part affected, an instrument has been invented, hut a portion of silver-wire formed into a loop, surrounding the cylinder near the base, is The moxa may be applied in various ways. "It may be used so as not to cause any injury ; iu a greater degree, so as to produce vesication ; and in a still greater degree, an eschar, which may be either deep or superficial; or it may be employed with the acupuncture needle." In the first form, it is burnt near, but not in contact with, the part affected, and is often of great service in healing indolent ulcers; it generally requires to be applied once a day. It is even used in some chronic inflammations of the eye with very good effect. In the second form it is also to be held near the skin, and continued till a blister results. In tic douloureux of very superficial nerves this is sometimes beneficial. The third mode is the most common, and for this the part to which the moxa is intended to be applied is marked out, and the moxa being surrounded with a piece of card-paper, which has been moistened with a solution of common salt, to protect the adjacent skin, the moxa is ignited at one end, and the combustion increased, if necessary, by means of a blow pipe. For the cure of obstinate sciatica and deep-seated diseases of the joints a frequent repetition of the moxa may be required, but it seldom fails to give relief. " When the moxa and acupuncture needle are used together, a moxa of a proper size is to be perforated by a needle of such a length as will be sufficient to reach the seat of the disease, and at the same time extend so far from the surface of the skin as to keep the moxa about one inch from it. The needle is then introduced, and the moxa is now put in a state of combustion, and the heat disengaged from it is communicated to the needle, and thence conveyed to the seat of the disease." [ACUPUNCTURE.] When the pain from the third mode of applying the mom is very great, a linseed-meal poultice will generally mitigate it, or liquor ammonia.
Prejudice against this remedy, on account of its apparent severity, has prevented its being extensively used, but almost all practitioners who have made trial of it can attest its efficacy. It will rarely be had recourse to, except in cases of a neuralgic or paralytic kind of such obstinacy or painfulness as to justify the measure; but in such diseases it should not be overlooked. Its application has dispersed the almost ossified nucleus of a goitre, which resisted all other means to effect its absorption. (Wallace, On the Action of Mo.ca.)