Very light low shoes, such as dancing shoes and slippers, the upper leathers of which are alone sufficient to keep them firmly on the foot, do no harm by the mode of their fastenings, but it is insufficient, and a more efficient contrivance is required for the ordinary boot or shoe.
The boot is fastened by firmly encircling the foot at the instep. The whole foot is so wedged in between upper leather and sole, that, as is well known, the pulling off of a boot very frequently necessitates the use of a boot-jack.
It is impossible that the foot can be thus tightly clasped without producing a constant pressure on the instep. What then are the consequences of this?
We have already seen that the foot forms an arch, the efficiency of which in a special manner depends on the tensity of its ligaments being maintained. If, then, an unnatural and flattening pressure be constantly exercised on this arch, the binding ligaments get slackened and the arch falls down; and a broken-down arch, as we have already seen, causes flat-foot. The pressure of the upper leather on the instep must therefore, and particularly in the case of narrow boots, favour the origin of this deformity. The same cause must further interfere with locomotion, for at every step the increased arching of the instep, which takes place the moment that the foot is set to the ground, is resisted by the upper leather, and an injurious influence is thus exercised on the action of some
