DISEASES OF THE FOOT—CANKER

New Zealand Mail, Issue 1612, 21 January 1903, Page 64

DISEASES OF THE FOOT—CANKER

A disease affecting the sole of the foot of the horse associated with what are called fungoid growths, occasionally occurs among the heavy breeds of horses, and is recognised as canker of the foot, owing to the presence, over the diseased membrane, of a large crop of funguslike bodies, giving to the bottom of the foot something of the appearance of the bark of a tree covered with lichens. The idea of the growths being of a fungoid character was maintained until it occurred to some observer with a microscope to pay some attention to the pathology of the disease. Naturally the first step in any investigation would be the examination of the morbid deposit under a high magnifying power. The result was entirely unexpected, and instead of any form of fungus, nothing was discovered hut the elements of horn; in other words, loosely scattered epithelial cells of which hair and horn are constituted. The result of the initial inquiry, in fact, Was another illustration of the ’ truth of the remark which was later on attributed to Virchow, who was reported to have stated that in disease no new structural elements are produced. Nothing, in short, hut normal tissue, which may he thrown out from the overcharged vessels in excessive quantities, constituting hypertrophy, or in the event of chronic inflammatory disease, the elements of the tissues may be deficient, or may he entirely misplaced, producing various forms of tumours and other derangements which are differently named according to their position and character. Thus an excess of bony material either on a hone or m a muscle or tendon, is known as an ossific deposit, or exostosis. A tumour which possesses a structure which js somewhat allied to that of the brain is described as encephaloid cancer. The presence of a large collection of epithelial cells constitutes epithelial cancer. In all these cases the microscopist would distinguish only the elements of normal structure, and this structure is eminently true in the case of the deposit on the secreting membrane of the foot. In canker, a slight scraping from the diseased membrane shows a quantity of epithelial cells, and a scraping of the healthy horn of the foot, after bemg macerated for a few minutes in a solution of potash, would present precisely the same appearances. The question then naturally arises, How does it happen that canker® is a serious, almost an incurable disease, when the diseased products are not to be distinguished from the healthy structure? The question, like many others in pathology, cannot he answered; there is evidently something in the deposit from the inflamed membrane which does not exist in that from the healthy membrane. What the something is lias not yet been discovered, probably because no pathologist has taken the trouble to* make a sufficiently accurate inquiry. There is no doubt, however, that there is something of malignant character- in canker, as proved by the tendency which the ’ disease exhibits to extend its area, until, if left unchecked, it will affect the whole of the secreting membrane, including the sole, frog, and even reaching to the lamella ted structure. There is very good ground for believing that canker is a constitutional affection ; at any rate, that there is a constitutional tendency which is an essential preliminary to the establishment of the local disorder, and there is also some evidence... that it is transmissible by inoculation. Experiments under this head, however, are not very conclusive, probably on account of the impossibility of deciding whether or not the subject selected for inoculation has the necessary susceptibility in the Canker may arise from almost any injury to the sole of the foot which is suffi-

cient to excite inflammatory action, bruises inflicted on the sole by a horse treading on a sharp stone or puncture from a nail, or even a neglected thrush, may all of them he followed by canker, presumably, only, however, in those animals which possess the constitutional tendency to the disease, otherwise the cases would be very much more numerous than they are. Symptoms of canker—the early indications of the malady—ore by no means marked, and this would naturally ho the case in a disorder which affects the vascular structure which is hidden from view by a dense covering of homy material. At the same time, it may be known that a horse is affected with thrush, probably in a very pronounced form, but it does not appear to he in most cases suspected that the bad form of thrrash may itself he incipient canker. It has been repeatedly suggested that canker is sometimes tii© consequence of the extension of the disease from the frog to the sole, and it is certainly true that in some cases of thrush, socalled, the homy frog is entirely thrown off during the progress of the disease, and the condition of the internal membrane is identical in appearance with the diseased sole in cases of canker; and it is not unreasonable to conclude, therefore, that one form of the disease which is described as thrush, merely because it is present in the frog, is in reality the first appearance of canker, which -will certainly extend over the membrane of the sole, with which the secreting membrane of the frog is continuous. In all such cases it is most important that the extent of the disease should he ascertained at once by paring do-wn the solo and removing all tne horn of the sole which is loosened from the membrane; and in many cases the operator will lie startled to discover that he has to get rid of a large portion of the horny sole before he reaches the fungoid deposit, and that, in fact), what he has been treating hitherto as a bad case of thrush was in reality canker, which had commenced in the frog and extended to the sole, or possibly had commenced in the sole and extended to the frog. It will at once he admitted that treatment of a disease of the serious character which has just been described is quite beyond the powers of the amateur. The great object is to apply a certain amount of pressure to the bottom of the foot which has to bo dressed with caustics and astringents. A very radical hut effectual method of treatment is the extirpation of the whole of the horny covering of the sole, the cutting away of all the fungoid growths, and the applicatio nof nitrate of silver or some other strong caustic. The whole of. the sole is then covered with dry tow, which is secured to the bottom of the foot, either by putting on a tar shoe with a leather sole, or preferably by enveloping the whole of the foot in a leather hoot. The dressings will require to he repeated in the course of two or three days, and continued until the homy covering, which is gradually secreted, is sufficiently nrin to require no further support.—“ The Field.”