Niddah, Chapter 9, Mishnah 7. Our Mishnah continues the discussion of kesamim, stains found on a garment whose origin is in doubt. A woman finds a mark on her clothing, and the question is whether that mark is blood, which would render her temeiah, or simply a dye that was already in the fabric. The Mishnah gives us a practical laboratory test.
The Mishnah names a fixed group of cleansing agents: "shiv'ah samanim", seven materials, which are "ma'avirim al hakkesem", rubbed across the questionable mark. Every one of them has the chemical strength to break blood down. That gives the examination a clear reading in either direction. A mark that yields and vanishes under them has been shown to be blood. A mark that survives all seven untouched could never have been blood at all, and must instead be a pigment that had soaked into the cloth beforehand.
The seven substances
- "Rok tafel": tasteless, or bland, saliva.
- "Mei grisin": water in which beans have been prepared.
- "Mei raglayim": urine.
- "Nesser": lye.
- "Boris": soap.
- "Kimonya": a type of earth or clay that was used as a cleansing agent.
- "Ashlag": an alkaline mineral, a potash-like substance, also used for cleaning.
The case the Mishnah presents
The Mishnah now applies the test to a case with real consequences. "Hitbilo": a person immersed the cloth in a mikveh in order to purify it, "ve'asah al gavav taharos": and then used that cloth in the handling of items that were meant to remain tahor, resting them upon it. Afterward a stain is discovered on the cloth, and now everything hangs in the balance: was the cloth tamei all along, in which case whatever was placed on it has been rendered tamei as well?
Here the seven substances decide the matter.
Take first the negative outcome. "He'evir alav shiv'ah samanim", the seven were applied to the mark, "velo avar", and it held fast and stayed put. In that case, "harei zeh tzeva": the Mishnah rules that the discoloration is nothing more than a dye. It follows that "hattaharos tehoros": whatever taharos were handled upon the garment keep their status untouched. And "ve'eino tzarich lehatbilo": no fresh immersion is required for the cloth, since no tumah ever attached to it in the first place.
"Avar, o shedehah": but if the stain came out, or even if it did not vanish entirely but merely grew faint and faded, "harei zeh kesem": it is treated as a genuine bloodstain. Consequently, "vehattaharos temeios": everything that was prepared upon that cloth is retroactively tamei, "vetzarich lehatbilo": and the cloth must be immersed in the mikveh again.
The lesson of the Mishnah is the honesty of a real test. The Chachamim did not leave the question of a doubtful stain to guesswork. They identified substances that blood cannot withstand, and let the fabric itself testify: whatever these seven cannot budge was never blood.