Shabbat 133 - All necessities of circumcision
Circumcision includes removing two layers of skin: the comparatively thick outer layer, called the foreskin, which covers the corona on the outside, and the thin membrane, which covers it on the inside. First the outer foreskin is removed, and then the membrane is pulled back. Then one who performs the circumcision draws the blood - for otherwise the accumulated blood would cause danger - and afterward the dresses up the wound.
All of the these operations are required for proper circumcision and are permitted on Shabbat. If one did not prepare an ointment, he may do so - albeit in an unusual manner. If he did not prepare a bandage in the right shape, he may not do so now - but he can wrap a cloth around the wound. If he did not bring the cloth before Shabbat, he may even bring it on Shabbat - but only through courtyards, not through the streets where carrying is forbidden.
Art: Jules Breton - Woman carrying Water