Niddah

Elsewhere we learnt: If potsherds which a zab has used  absorbed liquids and then fell into the air-space of an oven,  and the oven  was heated, the oven becomes unclean, because the liquid  would  ultimately emerge.  Resh Lakish stated: This  was learnt only in regard to liquids of a minor uncleanness  but in the case of liquids of a major uncleanness  the oven becomes unclean even though it was not heated.  R. Johanan stated: Whether the liquids were subject to a minor or a major uncleanness the oven is unclean only if it was heated but not otherwise. R. Johanan raised an objection against Resh Lakish: IF ONE IMMERSED IT AND, HAVING HANDLED CLEAN THINGS ON IT, APPLIED TO IT THE SEVEN SUBSTANCES AND THE STAIN DID NOT FADE AWAY, IT MUST BE A DYE; AND THE CLEAN THINGS REMAIN CLEAN AND THERE IS NO NEED TO IMMERSE IT AGAIN.  The other replied: Leave alone the laws of stains  which are merely Rabbinical.  But [R. Johanan objected] did not R. Hiyya teach, 'To that which is certain menstrual blood one may apply the seven substances and thereby neutralize it'?  — The other replied: If Rabbi  has not taught  it,  whence could R. Hiyya  know it? R. Johanan pointed out another objection against Resh Lakish: 'If a quarter of a log of blood  was absorbed in the floor of a house [all  that is in] the house becomes unclean,  but others say: [All that is in] the house remains clean. These two versions, however, do not essentially differ, since the former refers to vessels that were there originally  while the latter refers to vessels that were brought in subsequently.  Where 'blood was absorbed in a garment, and on being washed, a quarter of a log of blood would emerge from it, it is unclean, but otherwise it is clean!  — R. Kahana replied: Here they have learnt some of the more lenient rulings concerning quarters of a log [both referring to a mixture of clean and unclean blood]; [and the law of] mixed blood  is different  since it  is only Rabbinical.  Resh Lakish raised an objection against R. Johanan: Any absorbed uncleanness that cannot emerge is regarded as clean.  Thus it follows, does it not, that if it can emerge it is unclean even though it had not yet emerged?  — R. Papa replied: Wherever it  cannot emerge  and the owner did not mind absorption,  all agree that it is regarded as clean. If it can emerge and the owner does mind the absorption, all agree that it is unclean. They only differ where it can emerge but the owner does not mind its absorption. One Master  holds the view that since it can emerge [it is unclean], though the owner did not mind its absorption;  and the other Master  holds that although it can emerge