[Footnote A:  The inventor of this shoe uses the word ‘grip’ to denote what, in describing other expansion shoes, we term the ‘clip’ (H.C.R.).]

(a) Smith’s.—­For many years past continental writers have been practising this method.  So far as we know, however, Lieutenant-Colonel Fred Smith was the first English veterinarian to use a shoe of his own devising, and to report on its effects.  This shoe we will, therefore, give first mention.

The above figure, with its accompanying letterpress, sufficiently explains the nature of the shoe.  In fitting the shoe, care must be taken to have the hinges (f, f) far enough back, or the shoe will have a tendency to spring at the heels, and the grips (e, e), which catch on the bars, will have a difficulty in biting.  This trouble will be avoided by having the hinges about 1-1/2 to 2 inches from the heels.

After the shoe has been firmly nailed to the foot, the travelling nut b is driven forward on the screw a so as to cause the grips to just catch on the inside of the bars of the foot.  According to the inventor, the amount of pressure to be exerted must be learned by experience, and he says: 

’I screw up very gradually until I see the cleft of the frog just beginning to open.  I now trot the horse up, and if he goes sound it is certain that the pressure I have exercised will not give rise to trouble.  The animal is sent to work to assist in the expansion of the foot.  On examining the shoe next day, the grip is found to be quite loose, the foot has enlarged, and the nut is turned once more until the grip on the bars is tightened, the horse being again trotted to ascertain that no injurious pressure is exerted.

’Every day or two I repeat this process, making measurements in all cases before widening the heels.  The increase in width of the foot which results is astonishing, 1/4 to 3/8 inch during the first week may be safely predicted, and in a month to six weeks it is impossible to recognise in the large healthy frog and wide heels, the shrivelled-up organ of a short time before.’[A]

[Footnote A:  Journal of Comparative Pathology and Therapeutics, vol. v., p. 98.]

It is pointed out by the writer of the above (and his observations, doubtless, apply to the use of all other expansion shoes in which the bars are gripped and forcibly expanded) that the whole secret of success lies in avoiding injurious pressure by exerting too great an expansion at one operation.  After each manipulation of the expanding apparatus the horse should trot sound and the frog remain cool.  Should the foot become hot, and lameness supervene, then tension should at once be relaxed.

Recorded Cases of the Use of the Shoe.—­The inventor of the shoe relates two cases of contracted foot treated by these means in which the heels of one, after thirty-nine days’ treatment, had increased in width to the extent of 1 inch, and the heels of the other, after twenty-four days’, had enlarged 5/8 inch.  Of the first case he gives the drawings in Fig. 74.