Negaim, Chapter 4, Mishnah 8. This chapter has been occupied with the ways in which the simanim of tumah combine with one another and with the question of when a nega is still the same nega we were looking at before. Until now we have dealt with the pairing of se'ar lavan (white hair) together with michyah (a patch of healthy flesh inside the nega). Our mishnah moves on to the pairing of michyah together with pisayon, the spreading of the nega, and then to a series of changes in the nega that might, or might not, make us treat it as something new.
Before turning to the mishnah itself, it pays to have Rabbi Shimon's reasoning from the preceding mishnah in view. The case discussed there was a baheres consisting of ten adashim: nine of them white and holding two white hairs, while a michyah occupied the tenth adashah. When that michyah subsequently left, Rabbi Shimon pronounces the man tahor. That is not how we rule; we follow the chachamim, who hold him tamei. Nevertheless, the Tosfos Yom Tov shows us the source of Rabbi Shimon's position. He reads the Torah's word "v'se'ar" closely: the verse says se'ar, and not "se'ar miktzaso", hair produced by no more than a part of the baheres. On his view the white hair had to have been whitened by a complete baheres of a gris, and not by a fraction of one, such as nine adashim of whiteness with a michyah filling out the tenth. That is the thinking behind his ruling, even though the practical halachah lies elsewhere.
Why the case must be after hachlata
When the mishnah pairs michyah with pisayon, it must be describing someone who has already been declared a metzora muchlat, and the reason is simple. Michyah counts as a siman of tumah from the very first look, so were the kohen to find a michyah in the nega when he initially examines it, hachlata would follow on the spot. Spreading, by contrast, carries no weight at an opening examination; it takes effect only when the kohen returns after the first week of hesger, or after the second.
The Rav therefore frames the case this way. A baheres of a gris appeared, and the kohen closed the man up for a week. When the week was out and the kohen examined the nega again, he found two things in it: a michyah, which by itself would call for hachlata even at an opening examination, and a pisayon, which functions as a siman of tumah once a week of hesger has run its course. The kohen accordingly declared him a metzora muchlat. The mishnah now asks what happens should one of these two simanim disappear.
One siman goes, the other holds him tamei
The mishnah's opening clause is "halcha hamichyah": should the michyah leave, the ruling is "tamei mipnei hapisayon", he stays tamei because the spreading is still present, and this holds whether that spreading was observed when the first week of hesger ended or when the second did. The next clause is "halach hapisayon": if the spreading pulls back and the nega returns to the measure it had at the start, then "tamei mipnei hamichyah", the michyah left within it keeps him tamei. In either direction his standing as a metzora muchlat is unchanged.
"V'chein b'se'ar lavan u'pisayon": white hair together with spreading follows precisely the same rule. Once hachlata has taken place, the Rav notes, the loss of either one of the pair leaves the other in force to render him tamei, and his status does not budge: he continues as a metzora muchlat.
A baheres that leaves and returns
"Halcha v'chazrah b'sof shavua." The Rav paints a different picture here. The kohen had confined a man on account of a gris-sized baheres in which no siman of tumah was present. (The whiteness itself is no siman; it merely qualifies the spot for examination.) Midway through the hesger the white patch vanished entirely, and by the time the kohen came to look at him again once the week was over, it had reappeared. The mishnah's ruling is "harei hi k'mo shehayasa". We do not count this as a new nega but as the identical one, and so, as the Rav writes, the kohen confines him for a second period of hesger, just as he would have done had the baheres never gone away.
"L'achar hap'tur": the vanishing and the reappearance occur once the man has already been discharged. The Rav fills in the picture: the kohen's examination after the week found the baheres gone, and since it was still absent, he pronounced him tahor. "Im achareichen chazrah, teira'eh bat'chilah", a return here meaning a return in the same place. The baheres is now handled as a wholly new nega and inspected afresh. In practical terms, if the man had earlier been muchlat, he brings the korbanos for that earlier nega, which left him and restored him to taharah, and what confronts him now is a second nega whose whole reckoning starts over from the beginning.
A change in shade
"Haysa azah v'na'asis kehah, kehah v'na'asis azah." Suppose the baheres had been a vivid, strong white, the white of snow, and it then faded to a weaker shade such as the plaster of the Heichal or the skin of an egg; or the reverse, that it began among the fainter shades and brightened. The ruling is "harei hi k'mo shehayasa": its identity is untouched. Movement from one shade of white to another is no reason to treat the nega as a fresh one. One qualification is attached, "u'vilvad shelo tisma'et mi'daled mar'os": it must not dim past the four appearances altogether, fainter than k'rum beitzah, the membrane of an egg.
Shrinking and spreading, spreading and shrinking
"Kansa u'pasasa, pasasa v'kansa." The Rav unpacks both halves. In the first, a man was confined for a baheres measuring a gris, and when the week ran out and the kohen inspected him, the baheres had contracted to less than a gris. Later on, the ground it had given up filled in again, but not one bit beyond that; the nega is no bigger than it had ever been. In the second, the baheres spread when the first week of hesger closed, which ought to have produced hachlata, but before the kohen had finished weighing the matter the spreading drew back, and the nega stood once more at its original gris and no more.
The mishnah records a dispute over both of these. "Rabbi Akiva m'tamei": in his view the man is tamei, "sheharei pasah", since a spreading genuinely did take place. "V'chachamim m'tarin": the chachamim rule him tahor, on the grounds that "she'ein zeh pisayon", what happened does not qualify as spreading at all, since "harei hu k'mo shehayasa", when the dust settles the nega measures no more than it did at the outset. Whether it first drew in and then refilled, or first spread and then drew back before any declaration of hachlata, nothing has been added to the baheres. The Rosh in his peirush reads both cases as occurring after the p'tur, once the man had been found tahor and sent off, the question being whether what stands before us now qualifies as a new nega.
The Rav draws out the consequences of the chachamim's position. Should this situation present itself when the first week of hesger has run out, the kohen confines him for a second stretch of hesger. Should it present itself when the second week has run out, with the nega no larger than before and no pisayon to be found, the kohen discharges him and he is tahor, since that is the law of a baheres: absent spreading by the close of the second hesger, the man is tahor. And the halachah is as the chachamim say.