"Why must my pupil be forced always to have a cow's skin under his feet? What harm would there be if in case of need his own skin were able to serve him as a sole? In this part of the body the delicacy of the skin clearly can never be useful for anything and can often do much harm. Awakened at midnight in the heart of winter by the enemy in the city, the Genevans found their muskets before their shoes. If none of them had known how to march barefoot, who knows whether Geneva might not have been taken? Let us always arm man against unexpected accidents. In morning let Emile run barefoot in all seasons, in his room or on the stairs, in the garden. Far from reproaching him, I shall imitate him."
January 1, 1970
https://en.wikiquote.org/wiki/Feet