[Footnote A: The words in italics are alterations in the original article made by Mr. Malcolm in a private letter to the author (H.C.R.).]
'Although this test is certain for horn thinned to the quick, it is not to be relied upon with thick horn, the outside of which may be practically healthy and char black, while its underlying surface may be cankered. With this exception the test is an infallible one, as by it the demarcation between cankered and healthy tissue can be clearly traced, and as a result we can with equal confidence radically remove[A] all cankered tissue, and conserve all healthy. As the object of that abominably cruel and barbarous operation of stripping the sole is the exposure of all canker, and as this can be done with equal certainty with the aid of the hot iron, there can be no necessity for performing it. The pain of cauterizing cankered tissue, which is a necessary operation, is infinitesimal (canker largely destroying sensation), compared with the pain produced in the totally unnecessary process of tearing healthy horn from a highly sensitive tissue.
[Footnote A: The words in italics are alterations in the original article made by Mr. Malcolm in a private letter to the author (H.C.R.).]
'Having by means of the knife and cautery removed every known particle of disease, the next procedure is to pack the surface of the sole and frog thus exposed with a mild dressing, such as vaseline; but if the cankered surface has not been efficiently, scraped, than there is required a more [A] powerful astringent or caustic dressing, which may vary considerably according to the individual fancy. A great favourite of mine consists of equal parts of sulphates of copper, iron, and zinc, mixed with strong carbolic acid, a very little vaseline being added to give the mass cohesion. The dressing, covered by a pledget of tow, is held in position by a shoe with an iron or leather sole, and the dressing and tow together should be of sufficient bulk to produce slight pressure on the sole when the nails of the shoe are drawn up. This insures contact between the dressing and the exposed surface, as well as any benefit derivable from pressure.
[Footnote A: The words in italics are alterations in the original article made by Mr. Malcolm in a private letter to the author (H.C.R.).]
'The dressing of the foot and nailing of the shoe can usually be more expeditiously performed when the horse is on his feet than when prone. If only the frog, or the frog and a small part of the sole, be involved, the horse should be kept at work, but if a large part or the whole of the sole a few days' rest may be necessary; but as soon as the condition of the foot will allow, work should be resumed, and it is simply marvellous how sound a horse will walk while minus the greater part of his sole from canker.
'On the second day following the shoe should be removed, and the foot redressed. To effect this it is necessary to recast the horse. Commencing at the edge of the sound horn, at the most dependent part of the foot, all new horn, no matter what its condition, must be pared to the quick, especial care being taken to effectually remove any lingering disease. Want of success is frequently attributable to neglect of this precaution. A small particle of canker remains undetected, forms a new centre of infection, and just when success is anticipated, much to your chagrin you have to deal with a fresh outbreak of canker, instead of a rapidly-healing foot. Parenthetically, I may here remark that the amount of more or less imperfect new horn produced by a cankered surface after an effective but not too destructive cauterization is almost incredible, and one cannot fail to be struck with the very active proliferation here compared with the meagre production of new horn by the healthy surface.
'After all disease has been excised, carefully clean the foot with waste, thoroughly protect any raw surface resulting from overcauterization by some mild agent, such as a saturated calomel ointment, reapply an astringent dressing over the whole affected surface, and nail on the shoe. This method of procedure should now be thoroughly carried out daily for a time, and as it is proceeded with a successful issue soon becomes assured in nearly every case. Where, in spite of these efforts, the disease still persists, depend upon it the fault is with the operator, who has failed to eradicate some centre of infection. Under these circumstances it may be necessary to recast the patient, repare the foot, and by the aid of eye, knife, and cautery, endeavour to find the cause, and having found it, which can invariably be done, remove it. The usual treatment will then speedily become successful. As the case proceeds dressing every other day will soon be sufficient, then twice a week, and finally, once a week until sufficiently cured.
'During this healing process, and after the complete eradication of canker it may be again repeated, no agent seems to have a more beneficial effect than calomel, and for this purpose it is best used as a dry powder. Under this dressing any remaining spot of canker is readily detected by the wet condition of the calomel when the shoe is removed the next day. In dealing with such a spot, a very good plan, after all apparently diseased tissue has been excised, is to touch the cankered part with solid nitrate of silver, or a feather dipped in one of the strong mineral acids, and then reapply calomel over the surface. The result of this treatment is frequently very gratifying.
'In successful treatment the shoe must be removed each time—an adjustable plate will not do, as no man can thoroughly pare and examine a foot with the shoe on, and imperfect dressings are worse than useless. Indeed, it is better not to pare or thin the horn at all, than to imperfectly pare, since canker, if undestroyed, develops far more rapidly under thin horn than under thick.