Reference: Mishnah>> Seder Nashim>> Shabbat>> Chapter 19>> Verse 2
Online Read: http://www.sefaria.org/Mishnah_Shabbat.19.2?lang=en
Original Text: One may do whatever is necessary for a circumcision on Shabbat. One may circumcise, and tear [the membrane], and suck [the blood], and put a bandage and cumin on it. If he did not grind it [the cumin] on Shabbat eve he may chew it with his teeth and put it on. If he did not mix wine and oil on Shabbat eve he may put this by itself and this by itself. One may not prepare a dressing [on Shabbat] but he may wrap a rag around it. If he did not prepare it on Shabbat eve he may wrap it round his finger and bring [it] – even from another courtyard.