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.

A represents the foot before treatment; B the same foot after nine days'
treatment, when the heels had widened 3/4 inch; and C the same foot at
the end of the thirty-nine days' treatment, at which date the frog was an
excellent-looking one, and the foot had increased an inch in width.[A]

[Footnote A: _Journal of Comparative Pathology and Therapeutics_, vol. v.,
p. 100]

[Illustration: FIG. 74.--THE CHANGES IN FORM OF A CONTRACTED FOOT TREATED
WITH SMITH'S EXPANSION SHOE]

In 1893, at a meeting of the Midland Counties Vet