The appearances of Negaim [diseased patches on skin, clothes, or houses that create impurity] are two which are four: Baheret is bright [white] like snow, its subsidiary is like the lime of the Temple. Se'et is like the membrane of an egg, its subsidiary is like white wool; the words of Rabbi Meir. The Sages say, Se'et is like white wool, its subsidiary is like the membrane of an egg.

The Patukh [red-tinge] in the snow [white patch] is like wine poured into snow. The Patukh in the lime [patch] is like blood poured into milk. These are the words of Rabbi Yishmael. Rabbi Akiva says: The ruddiness of this [one] and that [one] is like wine poured into water, except that of the snow [patch] is brighter and that of the lime is duller than it.

These four appearances [of Negaim] combine, one with the other, to exempt [one from impurity], to decide [that one is impure], or to quarantine [one of uncertain status]. [They combine] to quarantine that which remains [unchanged] at the end of the first week [from reporting the Nega]. [They combine] to exempt that which remains [unchanged] at the end of the second week. [They combine] to decide that which develops healthy skin [in the area of the Nega] or white hair, [whether] initially, at the end of the first week, at the end of the second week, [or] after the exemption. [They combine] to decide that which develops spreading, [whether] at the end of the first week, at the end of the second week, [or] after the exemption. [They combine] to decide that which turns completely white, [coming] from [the state of] exemption. [They combine] to exempt one who turns completely white, [coming] from [the state of] the decision [that he was impure] or from quarantine. These are the appearances of Negaim which all Negaim are based upon.

Rabbi Chanania the vice of the priests says: The appearances of Negaim are sixteen. Rabbi Dosa ben Harkinas says: The appearances of Negaim are thirty-six. Akavia ben Mahalalel says: seventy-two. Rabbi Chanania the vice of the priests says: One may not examine the Negaim initially after Shabbat [in order to diagnose them] because then [the end of] his week [of impurity] will fall on Shabbat. And not on the second day [of the week] because then [the end of] his second week will fall on Shabbat. And not on the third day [of the week] for the case of [the Nega afflicting] houses, because then [the end of] its third week will fall on Shabbat. Rabbi Akiva says: One always examines. If [the end of the week] fell out on Shabbat, they would push off [the examination] until after Shabbat. And this matter has both leniency and stringency.

How [is waiting until after Shabbat considered] a leniency? [If] he had in [the Nega] white hair [on Shabbat] and [after Shabbat] the white hair disappeared from it, [or if] if there were white [hairs] and they blackened, [or if there were] one white and one black, and the two of them blackened, [or if the hairs were] long and they were shortened, [or if there were] one long and one short, and the two of them were shortened, [or if] a boil encroached upon the two of them or upon one of them, [or if] a boil surrounded the two of them or one of them, or divided them - [this refers to] a boil, a partly-healed boil, a burn, a partly-healed burn, or a Bohak [very white blemish]. [Other cases of leniency include if the skin] had a healed part and then the healed part went away, [or if the area of the Nega] was square and became circular or stretched, [or if a healed part of skin] was surrounded [by a Nega] and then [the Nega] moved to the side, [or if the healed part of skin] was concentrated and then became scattered, [or if] a boil came and went into [the healed part of the skin], surrounded it, split it, or diminished it - [this refers to] a boil, a partly-healed boil, a burn, a partly-healed burn, or a Bohak. [Other cases of leniency include if the Nega] had an extension and then the extension went away, or if the original [Nega] went away, or it decreased [so that] there was not between this one and that one [i.e. between the original and the extension] an [area of] a bean, [or if a] boil, a partly-healed boil, a burn, a partly-healed burn, or a Bohak separate between the original and its expansion. These are [cases in which waiting until after Shabbat is considered a] leniency.

How [is waiting until after Shabbat considered] a stringency? [If] he did not have in [the Nega] white hair [on Shabbat] and [after Shabbat] white hair grew in it, [or if] there were black [hairs] and they whitened, [or if] one was black and one was white and the two of them whitened, [or if the hairs were] short and they were lengthened, [or if there were] one long and one short, and the two of them were lengthened, [or if on Shabbat] a boil encroached upon the two of them or upon one of them, [or if] a boil surrounded the two of them or one of them, or divided them - [this refers to] a boil, a partly-healed boil, a burn, a partly-healed burn, or a Bohak - and went away [after Shabbat]. [Other cases of leniency include if the skin] did not have a healed part and then grew a healed part, [or if the area of the Nega] was circular or stretched and became square, [or if a healed part of skin] had from the side [a Nega] and then became surrounded, [or if the healed part of skin] was scattered and then became concentrated, [or if] a boil came and went into [the healed part of the skin], surrounded it, split it, or diminished it - [this refers to] a boil, a partly-healed boil, a burn, a partly-healed burn, or a Bohak - and went away [after Shabbat], [or if the Nega] did not have an extension and then grew an extension, [or if a] boil, a partly-healed boil, a burn, a partly-healed burn, or a Bohak separate between the original and its expansion and went away [after Shabbat]. These are [cases in which waiting until after Shabbat is considered a] stringency.