1 R. Zera said in the name of Samuel: If one made a knife red-hot and slaughtered with it, the slaughtering is valid, because [the effect of] the sharp edge precedes [the effect of] the heat. But, what about the sides [of the knife]? — The cut opens wide. The following question was raised: If one made a spit red-hot and struck with it, is the resulting wound to be regarded as a boil or as a burning? But what is the difference between the two? Even as it has been taught: A boil and a burning, each is declared unclean within seven days by one of two symptoms: by white hair, or spreading. Why, then, did the Torah deal with them separately? To teach you that they cannot unite one with the other. And we have learnt: What is a boil, and what is a burning? A wound caused by wood, or stone, or olive-peat, or the hot springs of Tiberias, or any wound that is not caused by fire, including a wound caused by lead just taken from the mine, is a boil. And what is a burning? A burn caused by a live coal, or hot ashes, or boiling lime, or boiling gypsum, or any burn that is caused by fire, including a burn caused by water heated by fire, is a burning. And it was further taught: In the case of [a wound which is both] a boil and a burning, if the boil came first then the subsequent burning annuls the boil [and it is considered a burn]; but if the burning came first then the subsequent boil annuls the burn [and it is considered a boil]. Now the circumstances of our case are as follows: A man had a boil of the size of half a bean, and was struck close to it with a red-hot spit, another wound of the size of half a bean resulting, [making the whole wound the size of a whole bean]. In such a case how [are we to consider the resulting wound]? Did the force of the blow take effect first, and the burn caused by the glowing heat that followed annul the effect of the blow, so that the whole wound is composed of a boil and a burning [each to the extent of half a bean] which do not unite [to make him unclean]? Or did the glowing heat take effect first, and the force of the blow that followed annul the effect of the glowing heat, and consequently the whole wound is composed of two boils [each to the extent of half a bean] which unite [to make him unclean]? Come and hear: R. Zera said in the name of Samuel: If one made a knife red-hot and slaughtered with it, the slaughtering is valid, because the effect of the sharp edge precedes the effect of the heat. It thus proves that the force of the blow precedes [the glowing heat]! — No; in the case of a sharp edge it is different. Come and hear: If one was struck with a red-hot spit, the resulting wound is regarded as a ‘burning by fire’. It thus proves that the force of the blow precedes [the glowing heat]. — No; here too, the wound was made by a thrust with the point, which is a sharp edge. R. Nahman said in the name of Rabbah b. Abbuha: A knife which has been used in connection with idolatrous services may be used for slaughtering, but it may not be used for cutting up meat — ‘It may be used for slaughtering’, for thereby one impairs [the value]; ‘but it may not be used for cutting up meat’, for thereby one enhances [the value], Raba remarked: There are times when one may not slaughter with it, to wit, if the animal is at the point of death; and there are times when one may cut up meat with it, to wit, if the meat was in large pieces intended for a present. But should not the prohibition thereof be considered on account of the forbidden fat? 19ᵃᵇᶜᵈᵉᶠᵍʰⁱʲᵏˡᵐⁿᵒᵖᵠʳˢ
2 — It was a new [knife]. If new, [it should not be prohibited at all, since] it is merely an appurtenance for the worship of idols, and appurtenances of idols, both according to R. Ishmael and R. Akiba, are not forbidden till actually used in idol worship. — If you wish I can answer: It was used for cutting up wood for the idol; or if you wish I can answer: It was an old knife which was cleansed in the fire. It was stated: If a man slaughtered with the knife of a Gentile, Rab says. He must pare (the flesh]; Rabbah b. Bar Hana says: He need only rinse it. Shall we say that their difference lies in this: One holds the view that the throat is cold. while the other holds the view that it is hot? No. All hold the view that the throat is hot; therefore, he who says: ‘he must pare it’, is clearly understood, but he who says that he need only rinse it [argues thus]: while the organs [of the throat] keep on spurting out blood they will not absorb [any fat from the knife]. Some there are who state as follows: All hold the view that the throat is cold; therefore, he who says: ‘he need only rinse it’.is clearly understood, but he who says that he must pare it [argues thus]: by reason of the pressure of the knife [the flesh] must absorb [to some extent]. A knife which was used for slaughtering an animal found to be trefah, is the subject of a dispute between R. Aha and Rabina. One says, [It must be cleansed] with hot water; the other says. [It may be cleansed even] with cold water. The law is: Even with cold water. And if there is at hand a piece of cloth wherewith to wipe [the knife], nothing more is required. Now what is the reason of the one who says that it must be cleansed with hot water? It is [is it not] because it absorbed forbidden fat? If so, even after slaughtering an animal which is permitted to be eaten it should also require [cleansing with hot water] because it absorbed [the fat] of the limbs of a living animal? — [It is not so;] for [the knife] absorbs [the fat] only when [the throat] is hot, and it becomes hot only at the end of the slaughtering when the animal is ritually permitted. Rab Judah said in the name of Rab: A butcher requires three separate knives, one for slaughtering, one for cutting meat, and one for cutting away the [forbidden] fat. But why should he not use the same knife first for cutting meat and then for cutting fat? — It is forbidden to do so lest he cut with it the fat first and then the meat. Well, even now, he might get them mixed! — No; since he must have two separate knives he will make a distinguishing mark on each. Again Rab Judah said in the name of Rab: A butcher requires two separate pails of water, one in which he washes the meat and one in which he washes the fat. But why should he not use the same pail for washing in it first the meat and then the fat? — It is forbidden to do so lest he wash in it the fat first and then the meat. Well even now, he might get them mixed! — No; since he must have two separate pails he will make a distinguishing mark on each. Amemar said in the name of R. Papa: One should not place the loins on top of other meat for fear that the fat [attached to the loins] will run and will be absorbed by the meat. If so, why not apprehend the same even when the loins lie in their natural position, namely, that the fat [upon the loins] will run and will be absorbed by the flesh [of the loins]? — There is a membrane underneath [the fat of the loins] which separates it [from the flesh of the loins]. But then,ᵗᵘᵛʷˣʸᶻᵃᵃᵃᵇᵃᶜᵃᵈᵃᵉᵃᶠᵃᵍᵃʰᵃⁱ