Diseases of the Horse's Foot

by H. Caulton Reeks

This method of 'plugging,' although practised by many, we cannot recommend in preference to the use of the hot iron or of liquid injections. Our reasons are these: the action of the drug is a protracted one. Almost immediately after its introduction into the fistula there is formed about it an almost impermeable layer of a metallic albuminate, which effectively prevents further rapid action of the caustic. In addition to thus preventing further action of the dressing, this combination of the tissue albumin with the metal of the salt, together with much necrotic tissue that it has caused, is extremely hard to remove from the healthy tissues. This we explain by pointing out that the action of the caustic, prolonged as it is, sets up a tissue reaction which partakes largely of the type of a chronic rather than an acute inflammation. With a chronic inflammation there is sooner a tendency to the production of fibrous tissue (and thus the firmer attachment of the necrosed portions) rather than an active phagocytosis and the casting-off of a slough. Again, careful though we may be with the probe, it is extremely difficult to be certain that we have discovered the whole extent of any fistula. An equal difficulty, therefore, exists in being certain that we have placed the caustic in the position in which it is most wanted—namely, at the furthermost end of the fistula where the necrotic tissue is to be found.

When a caustic is used at all, it is far better to employ it in the liquid form, when either of the drugs we have just mentioned may again be used. In the first place, the liquid is far more likely to be brought into contact with the diseased structures than is the solid salt. Also, its action may be regulated by altering the strength of the solution, and the liability to form impermeable albuminates thus diminished.

Probably the best solution for use in this way is the old-fashioned Villate's solution (see p. 199).

This liquid should be injected at least every day, and, in a bad case, even two or three times daily. Practical hints to be borne in mind when attempting to cure quittor by means of injections are these:

If the fistulas are numerous, the fluid should be injected into their various orifices.

In order to force the fluid to the bottom of each diseased track, it is necessary, when injecting one opening, to firmly close all others.

Several injections should be made at each time of injection. In other words, we must not be content with just forcing fluid in. It must be forced in, and again forced out by a further syringeful. The fistulous tracks must, in fact, be washed in the liquid.

The effect of the injection during the first eight or ten days is to render suppuration more abundant and whiter. After two weeks of the treatment sloughing of the inside of the sinuses occurs, and healing of the wound commences. Signs that this is occurring are—slight hæmorrhage at the end of each injection, and a gradually increasing difficulty in forcing in the fluid.

The Making of Counter-openings to the Fistulas.—Although Villate's solution or any other caustic used in the manner we have described often effects a cure, many practitioners insist on the fact that a counter-opening to the fistula must also be made.

The probe is used and the direction and depth of the fistula ascertained. Through the wall is then made an opening at exactly opposite the lowest point found by the probe, or through the sole if the probe should there lead us. This opening is best made with a sharp-pointed iron, and may afterwards be kept large enough by an occasional trimming with the knife. Many of the older authors, and with them writers of the present day, declare that unless this is done the ordinary injection is likely to fail in a great many instances where it would otherwise have been successful.