Commentaire sur Nega'im 9:1

השחין והמכוה מיטמאין בשבוע אחד – if in their place (i.e., the boil or the burning) was born/originated the bright white spot on the skin, we shut him up/quarantine/isolate him and at the end of one week if there is white hair or spreading, he (i.e., the Kohen) declares him to be a certified leper, and if not, he releases him. But with quick flesh he is not defiled, for quick flesh requires live flesh, and this is not live flesh since in its place is boils and burning.

Introduction Chapter nine deals with a nega that forms in a boil or a burn. This is dealt with in Leviticus 13:18-28.

גפת (a pressed hard mass, peat, turf)- refuse of olives, and it is hot on account of itself. And similarly, the hot springs of Tiberias through the heat of their source they are hot and not in consequence of the fire.

A boil or a burn may become unclean in a week and by two signs: by white hair or by a spreading. As we learned in 3:4, when it comes to a nega in a boil or burn, only white hair and spreading are signs of impurity. Quick flesh is not. And there is only one week of isolation, not two as there are with other negaim.

כל שאינו מחמת האש זהו שחין – to include the lead directly from the mine (hot – see Tractate Hullin 8a).

What is a "boil"? An injury received from wood, stone, peat, or the waters of Tiberias, of from any other object whose heat is not due to fire is a boil. What I have translated as "boil" is really an inflammation due to contact with something hot other than fire. "Peat" is the refuse from the pressing of olives and it can be very hot when removed from the press. The waters of Tiberias are hot springs.

רמץ (hot ashes, embers) – the ashes of a portable stove on feet (with caves for two pots). And it is hot on account of the fire.

What exactly is a "burn"? A burn caused by a live coal, hot embers, or any object whose heat is due to fire is a burning. A burn is from contact with something that had contact with fire.

כל שהוא מחמת האש – and it is hot from the effect of/in consequence of the fire. כל שהוא מחמת האש – to include the heat of the fire.