There are [stringencies] that apply to living skin which do not apply to expansion, and there are [stringencies] that apply to expansion which do not apply to living skin: Living skin renders tamei initially, and renders tamei with any appearance. There are [stringencies] that apply to expansion: Expansion renders tamei with any amount, renders all negaim tamei, [and renders tamei] outside the nega, which is not the case with living skin.

There are [stringencies] that apply to white hair which do not apply to living skin, and there are [stringencies] that apply to living skin which do not apply to white hair: White hair renders a boil-nega and a burn-nega tamei, [renders tamei] whether together or spread apart, whether surrounded or not. There are [stringencies] that apply to living skin: Living skin renders tamei on a bald area on either the back or the front of the head, whether changed [by the nega] or not, prevents one who turns completely white [from becoming tahor], and renders tamei with any appearance, which is not the case with white hair.

Two hairs that are turning black at the root and white at the top are tahor [i.e. they are not symptoms of tumah]; if they are turning white at the root and black at the top they are tamei. How much of the hair must be white? R’ Meir says: Any amount. R’ Shimon says: Long enough to be cut with a pair [of scissors]. [If] it is one [hair] that splits [so that it] appears to be two [hairs], it is tahor. A snow-white nega that has white hair or black hair is tamei; we are not concerned that the black hair reduces the size of the baheres [until it is too small to become tamei], because [the hair] does not have any substantive [thickness].

A baheres the size of a gris has a strip [of nega] extending from it. If [the strip] is two hairs wide, it connects the baheres to white hair or to expansion, but not to a section of living skin. Two beharos have a strip [of nega] connecting them. If [the strip] is two hairs wide, they combine, and if not, they do not combine.

A baheres the size of a gris contains living skin the size of a lentil, and on the living skin there is white hair. If the healthy skin disappeared, [the baheres] is tamei because of white hair. [If] the white hair fell out, [the baheres] is tamei because of living skin. R’ Shimon considers it tahor because the baheres did not cause [the hair] to change color. A baheres, and the living skin it contains, together equal the size of a gris, and there is white hair inside the baheres. [If] the living skin disappeared, it is tamei because of the white hair. [If] the white hair fell out, it is tamei because of the living skin. R’ Shimon considers it tahor because [the hair] was not changed by a baheres the size of a gris. However, he agrees that if there is a gris [of nega] where the white hair [grows], it is tamei.

A bahereshad both living skin and an expan-sion. [If subsequently] the living skin disappeared, [the nega] is [still] tamei because of expansion. [If] the expansion disappeared, [the nega] is [still] tamei because of living skin. The same rule applies to white hair and to expansion. [If the nega] went away and returned at the end of the week, it is treated as if it remained unchanged. [If the nega went away, and returned] after it was declared tahor, it is examined anew. If [the nega] was bright and became dull, [or it was] dull and became bright, it is treated as if it remained unchanged, as long as it does not become less [bright] than the four shades. If [the nega] contracted and then expanded, [or] it expanded and then contracted, R’ Akiva renders it tamei, and the Sages render it tahor.

A baheres the size of a gris expanded by half a gris, but half a gris of the original baheres disappeared. R’ Akiva says: It must be examined anew, and the Sages render it tahor.

A baheres the size of a gris expanded more than half a gris, but half a gris of the original baheres disappeared, R’ Akiva renders it tamei, and the Sages render it tahor. A baheres the size of a gris expanded by more than a gris, but the original baheres disappeared. R’ Akiva renders it tamei, and the Sages say: It must be examined anew.

A baheres the size of a gris expanded an [additional] gris. Living skin or white hair [then] appeared inside the expansion, and the original nega disappeared. R’ Akiva renders it tamei, and the Sages say: It must be examined anew. A baheres half the size of a gris has no [other symptoms] inside it. [Another] baheres half the size of a gris appears, which has one [white] hair. This nega is confined. A baheres half the size of a gris has one [white] hair. [Another] baheres half the size of a gris appears, [also] having one [white] hair. This nega is confined. A baheres half the size of a gris has two [white] hairs. [Another] baheres half the size of a gris appears, containing one [white] hair. This nega is confined.

A baheres half the size of a gris has no [other symptoms] inside it. [Another] baheres half the size of a gris appears that has two hairs. This nega is confirmed, because [the Sages] stated: If the baheres preceded the white hair, [the afflicted person] is tamei, but if the white hair preceded the baheres, he is tahor. If it is uncertain, [the afflicted person] is tamei, but R’ Yehoshua disapproves [of this ruling].

Any doubt concerning negaim is ruled tahor, except for this [last] case and [the next] one. And what is [the next case]? Someone had a baheres the size of a gris that [the Kohen] confined. At the end of the week [of confinement], it was the size of a sela, [but] it is uncertain whether this is [the original nega that spread] or a different [nega] that replaced it. [The Kohen rules it confirmed] tamei.

[The Kohen] confirmed [a nega] because of white hair, which [then] disappeared. Subsequently, either the white hair reappeared, or living skin or expansion appeared. [Whether the original white hair had appeared] initially, after the first week, after the second week, [or] after the nega had been declared tahor, [the status of the nega] does not change. [The Kohen] confirmed [a nega] because of living skin, which [then] disappeared. Subsequently, either the living skin reappeared, or white hair or expansion appeared. [Whether the nega was originally confirmed] initially, after the first week, after the second week, [or] after it had been declared tahor, [the status of the nega] does not change. [The Kohen] confirmed [a nega] because of expansion, which [then] disappeared. Subsequently, either the expansion reappeared or white hair appeared. [Whether the original nega was initially confirmed] at the end of the first week, at the end of the second week, [or] after it was declared tahor, [the status of the nega] does not change.

‘‘Deposited hair’’ — Akavya ben Mahalalel rules it tamei and the Sages rule it tahor. What is ‘‘deposited hair’’? Someone had a baheres with white hair. The baheres disappeared, leaving the white hair in place, and [subsequently] returned. Akavya ben Mahalalel rules ‘‘deposited hair’’ to be tamei, and the Sages rule it tahor. R’ Akiva said: ‘‘I agree that this case is tahor [because it is not ‘deposited hair’]. What is ‘deposited hair’? Someone had a baheres the size of a gris that contained two [white] hairs. [The baheres] receded half a gris, leaving the white hair on the remaining baheres, and [subsequently] returned.’’  They said to him: ‘‘Just like Akavya’s opinion is disregarded, so is your opinion not upheld.“