Cupping.
—By the application of “cups,” blood is drawn to the surface, but ordinarily not abstracted, unless the surfaces have been previously scarified or incised. Dry cupping has the effect of attracting blood to one portion of the body, thus drawing it from another and congested part. It has the temporary effect of a venesection. Cupping glasses are small tumblers which are rinsed in alcohol; their edges are wiped and the remaining film within the glass is ignited from a candle or flame. The glass is then instantly applied to the affected area. The oxygen within the contained air is sufficiently consumed to create a slight vacuum and the skin quickly becomes congested, being sucked upward into the glass. These cups may be allowed to remain for a few moments, or until they drop off. Care should be exercised with alcohol and a lighted lamp around a patient who may be unconscious or excitable, as serious burns have followed carelessness in this regard. Small vacuum pumps, like the Allen surgical pump, have been provided for this purpose, and give very satisfactory results.
There was formerly employed for the purpose of wet cupping a small spring instrument, containing several sharp knives, by which a series of incisions were made in order that blood might be drawn. This instrument cannot be kept clean and is not used at present. When wet cupping is desired the part should be scarified with a sharp knife and the cup applied as above.
Leeching.
—Leeches figure largely in literature of the past, but are not often used, although they may be made effective, especially when applied behind the ears in cases of cerebral congestion. The American leech can be relied on only to abstract about a teaspoonful of blood, while the Swedish will draw three or four times that amount. The region to which they are applied must be washed, and, if necessary, shaved. The part should then be smeared with milk, blood, or sugar-water. The leeches should be put in a basin of fresh water, after which they are placed upon a dry towel for two or three minutes. Each one is then taken up in a small glass or test-tube and inverted over the spot chosen. As soon as the animal fastens itself upon the skin the glass may be removed. Leeches are often capricious and will sometimes wait considerable time before attaching themselves. When full of blood they usually relax and drop. If it be desired to remove them a little salt will make them relax. Leeches should never be applied over loose cellular tissue nor over superficial vessels or nerves. If used in the interior of a cavity they should be prevented from passing too far.
COUNTERIRRITATION.
Counterirritation is a valuable means of accomplishing that which is sometimes induced by leeches—namely, attracting blood to the surface for the relief of deep congestion. In fact it comprises more than this, since there is some deep influence exerted through the medium of the nervous system; it not only equalizes the circulation, but tranquillizes a disturbed innervation. The milder and more domestic means include the use of the so-called rubefacients—hot water, mustard, and turpentine. These are of little use in surgical conditions which call for counterirritation; their use should be controlled with caution lest mere counterirritation be converted into actual burning.
By the use of vesicants a blister is produced, i. e., an effusion of serum and lymph beneath the superficial and outside of the deeper layer of the skin. Mustard and cantharis are the principal vesicants in common use. The former may be used in full strength, in which case it is active, or it may be reduced with wheat flour or linseed meal. To bring out the full strength of mustard, hot water should not be used in its preparation, as it renders it almost valueless. A mustard paste or plaster should be watched at intervals, and it should be removed when the desired effect has been obtained—at all events, when the surface to which it has been applied is covered with vesicles.
Cantharis, or Spanish fly, is used either in the form of the cantharidal cerate or mixed with collodion, the latter being the neatest and most pleasant preparation. Several layers are painted on the surface where its effect is desired. This is then protected, and vesication will be found to have been produced within an hour or two, except where the skin is most resistant. The stronger chemicals, like ammonia, chloroform, strong iodine, and nitrate of silver solutions, will be found to be active blistering agents, but should be used with caution.
Two other methods of irritation were at one time in favor—namely, the seton and the issue. The former consisted of a bundle of threads or a wick, drawn into a large needle with a lancet-shaped point; the skin was picked up into a fold, the needle made to traverse it, and the wick was thus drawn through and cut off, so as to be left in place. The issue was made by drawing a blister with a powerful agent, and then preventing it from healing by the use of an irritating foreign body. These procedures have been abandoned by the medical profession, but are still in vogue among veterinary surgeons.