(Mishnah in Bechoros): (See earlier 19-1(j)) Rebbi Yehudah says that a Bechor (firstborn) that was taken by a blood congestion, even if it will die, one cannot let its blood. The Chachamim say that he may let as long as he does not make a blemish. If he did make a blemish, he may not slaughter it. Rebbi Shimon says that one may let its blood even if he will make a blemish.

(Rebbi Abahu quoting Rebbi Elazar): Rebbi Yehudah is following the opinion of Raban Gamliel (of the case of the first barrel); the Chachamim are following Rebbi Eliezer (that one is commanded to guard the Bechor although one may not make a blemish in the process) and Rebbi Shimon (who allowed making a blemish before it dies in order to make it permitted to eat) is following Rebbi Yehoshua (who allowed being Metamei the wine before it arrived in the lower winepress in order to make it permitted to eat).

Question (Beraisa quoting Rebbi Shimon): One may let its blood even if his intent is to make a blemish (thereby permitting it be eaten). This follows the other statement of Rebbi Yehoshua (in the case of the second barrel, that one may actively be Metamei it in order to save the Chulin below).

Answer (Rebbi Bun to Rebbi Zeira): That Beraisa (in (c)) is discussing Kodshim to which he is responsible. (In such a case, Rebbi Shimon holds that it is in the possession of the owner. He may therefore blemish it even intentionally).

(Rebbi Abahu quoting R''SBL): The source for Rebbi Yehudah (in (a)) is the pasuk that states (Devarim 12,24) "You shall not eat it, you shall spill it on the ground like water''. I only permitted you to spill its blood, i.e. to slaughter it when the blood is not needed or to spill all of the blood; but it is not permitted to let the blood.

Question (Aba Mari): Even concerning animals that are pasul to sacrifice, the pasuk states "You shall not eat it, you shall spill it on the ground like water''. However, all agree there that its blood may be let?!

Answer (Rebbi Chiya): The words "like water'' are used to teach that the blood from slaughtering will be machshir foods to become Tamei - just as water is machshir, so the blood is machshir.

Rebbi Abahu quoting Rebbi Yochanan: Both (Rebbi Shimon and the Chachamim) learn it from the same pasuk - (Vayikra 22,21) "It will unblemished to find favor, there will not be any blemish in it.''

Rebbi Shimon says that at a time when it is finding favor, there may not be a blemish; but when it is not finding favor (such as a Bechor that was taken by a blood congestion), there may be a blemish.

The Chachamim say even if it was covered in blemishes, one may not make in it a blemish. (They learn this from the extra word "kol moom'' - any blemish.)