Any doubt regarding Negaim [diseased patches on skin, clothes, or houses that create impurity] is considered pure except for this [the following case] and another. And which is [this case]? Someone who had upon him a Baheret [type of diseased patch that creates impurity] like [the size of] a bean, and quarantined it, and behold at the end of the week it was the size of a Sela [coin bigger than a bean, but] it is doubtful whether it was it [the original Nega] or whether another [Nega] had come in place of it, [this case is ruled] impure.

[If] he decided it [to be impure] by its white hair [seen in the Nega], [if] the white hair went away and then the white hair reappeared, and so too [if the hair was replaced with] a healthy patch of skin or an expansion, [whether he decided it by its white hair] initially, at the end of the first week, at the end of the second week, or after it was exempted, behold it returns to its previous status [of impurity]. [If] he decided it [to be impure] by a healthy patch of skin [seen in the Nega], [if] the healthy patch of skin went away and then the healthy patch of skin reappeared, and so too [if the patch was replaced with] white hair or an expansion, [whether he decided it by its healthy patch of skin] initially, at the end of the first week, at the end of the second week, or after it was exempted, behold it returns to its previous status [of impurity]. [If] he decided it [to be impure] by an expansion [of the Nega], [if] the expansion went away and then the expansion reappeared, and so too [if the expansion was replaced with] white hair, [whether he decided it by its expansion] at the end of the first week, at the end of the second week, or after it was exempted, behold it returns to its previous status [of impurity].

The hair of Pekudah - Akavya ben Mahalal'el declares impure and the Sages declare pure. What is the hair of Pekudah? Someone who had upon him a Baheret with white hair in it, [if] the Baheret disappeared and left white hair in its place, and then returned - Akavya ben Mahalal'el declares it impure and the Sages declare it pure. Rabbi Akiva said: "I agree [with the Sages] in this [case] that it is pure." What is the hair of Pekudah [about which Rabbi Akiva disagrees with the Sages]? Someone who had upon him a Baheret like [the size of] a bean with two [white] hairs in it, and then [the size of] half a bean went from it and left the white hair in the area of the Baheret and [then] returned. They [the Sages] said to him: Just like they discredited Akavya’s words, so too your words will not be established [as law].

Any doubt regarding Negaim initially is considered pure, until it has been obligated in impurity. Once it has been obligated in impurity, its doubt is considered impure. How so? Two who came to a priest, one with a Baheret like [the size of] a bean, and one like a Sela. At the end of the week [of quarantine], one is like a Sela and the other is like a Sela, but its unclear which one expanded. [This law applies] whether it was one person [with two Negaim] or two people, it is considered pure. Rabbi Akiva says: Regarding one person, it is impure but regarding two people, it is pure.

Once [the Nega] has been obligated in impurity, its doubt is considered impure. How so? If two [people] came to a priest, one with a Baheret like [the size of] a bean, and one like a Sela. At the end of the week [of quarantine], if one is like [the size of] a Sela and more and the other is like [the size of] a Sela and more, both of them are impure. Even if [their Negaim] return to both be like [the size of] a Sela, they are impure until they return to be like [the size of] a bean. This is as they said: Once it has been obligated in impurity, its doubt is considered impure.