"And she opened the skin of milk" (Judges 4:19). Concerning this our rabbis taught: there are nine fluids of a person experiencing a flux [zav]: sweat, foul discharge, and excrement, and the rest. Of all of them these are clean [and do not convey his severe impurity]; the tear of his eye, the blood of his wound, and a woman's milk convey only the impurity of liquids, in the measure of a quarter-log; but his flux, his spittle, and his urine convey severe impurity. The tear of his eye, as it is written, "And You gave them tears to drink [in great measure]" (Psalms 80:6). The blood of his wound, as it is written, "And drink the blood of the slain" (Numbers 23:24) — for what is the difference to me whether he killed him wholly or killed him in part? A woman's milk, as it is written, "And she opened the skin of milk" (Judges 4:19). Wine, from where? As it is written, "Every jar shall be filled with wine" (Jeremiah 13:12).
The Nine Fluids of the Body and Their Laws of Purity
Yalkut Shimoni on Nach 45:1
ותפתח את נאד החלב. שבו רבותינו ט' משקי זב הם זיעה וליחה סרוחה והרעי וכו', טהורים מכלם דמעת עינו ודם מגפתו וחלב שבאשה מטמאין טומאת משקין ברביעית אבל זובו ורוקו ומימי רגליו מטמאין טומאה חמורה. דמעת עינו דכתיב ותשקמו בדמעות, דם מגפתו דכתיב ודם חללים ישתה מה לי קטליה כוליה מה לי קטליה פלגא. חלב שבאשה דכתיב ותפתח את נאד החלב. יין מנין דכתיב כל נבל ימלא יין: