Negaim, Chapter 10, Mishnah 2. Before we open this mishnah, it is worth pausing to see where we stand in the masechta. Negaim come in six categories: four of them appear on a person himself, one appears on begadim (garments), and one appears on batim (houses). Almost everything we have learned so far, the opening eight chapters, dealt with negei basar, a nega on plain skin: the baheres in its four grades of white, and in the mixtures of those whites with red. Three simanim can render such a nega tamei: shtei se'aros, a pair of hairs that were dark and have since turned white; michya, an island of normal healthy skin surrounded by the nega; and pisyon, the nega's spreading. Should the kohen, at his very first examination, find that the baheres has produced white hairs, or that there is a michya inside it, the man is pronounced muchlat immediately. Pisyon cannot possibly be identified at a first viewing; only after a week of hesger can spreading be recognized. The hesger may run for as many as two weeks, and if at their conclusion the nega is unchanged and no siman tumah has surfaced, the man is tahor. Should a siman tumah surface, he is a metzora muchlat.
In chapter nine we moved on to two additional categories, shechin and michvah, a boil and a burn. In those cases the hesger runs for one week only, not two, and just two simanim render them tamei: se'ar lavan, hairs that were once dark and turned white, and pisyon. Even the pisyon there is limited in scope: the nega may spread out of one shechin into a neighboring shechin, or spread further within the same shechin, and correspondingly from one michvah into a michvah alongside it, or within that very michvah, where the baheres borders on it. Spreading counts as pisyon only in these ways.
Our chapter now turns to yet another variety of nega that appears on a person: the nesakim.
The mishnah's opening statement
The mishnah begins: "Hanesakim mitam'in bishnei shavu'os uvishnei simanim: bese'ar tzahov dak uvifisyon." Nesakim, like the ordinary baheres, can pass through two possible weeks of hesger. And they have two simanei tumah: se'ar tzahov dak, a thin yellow (golden) hair, meaning two such hairs, and pisyon, spreading.
The Rav explains at once what a nesek is: "Hanesakim negaim shebarosh o bezakan." These are the negaim that appear in the hairy regions of the body, the area of the beard or the area of the scalp where hair grows. They are called nesakim from the word lenatek, to tear away or remove, because through the nega the hair is loosened from its place, falls out and is uprooted.
Nesakim are not bound to the four mar'os
The Rav then reminds us of a point that has come up before but needs to be said again here: "Vehanesakim ein mitam'in bedaled mar'os keneged shebimekom basar." The nesakim are not confined to the four shades of white and their four reddish admixtures that we learned regarding a nega on ordinary flesh. It is quite likely that in most cases of nesek the discoloration does fall into those familiar shades, but the halacha is not limited to them. Any abnormal, unnatural coloring that appears on the beard or on the scalp can be a nesek: "Ela mitam'in bechol mar'os", in any coloration at all.
As for the hair itself, se'ar tzahov means a hair whose color resembles the hue of gold. And it must be dak. What exactly does dak mean? That is the subject of the dispute that fills the rest of the mishnah.
Rebbi Akiva: dak means short
The pasuk describes a nesek in which there is found a "se'ar tzahov dak", a hair of golden color that is also dak. What is dak? Rebbi Akiva's definition, in the mishnah's words, is "lakui katzer" (and the mishnah then adds "divrei Rebbi Akiva"). Lakui carries the sense of stricken or lessened, and the Rav reads it as joined to dak, describing the hair: it is a diminished hair, meaning a short one.
The Tosfos Yom Tov cites the Rambam, who takes lakui in a different direction entirely, applying it to the golden color: since gold is a blend of red and yellow, it is a weakened, diminished form of red, and that is what lakui conveys. The Rav, however, holds that the word speaks about the nature and texture of the hair.
Within Rebbi Akiva's view that dak means short, there are two ways of measuring that shortness. Some understand that the hair is shorter than the other hairs around it. Others understand that it is shorter than the shiur we already met by se'ar lavan on a baheres, where the hair had to be long enough to be caught and cut by a scissors; here the golden hair is shorter than that.
Rebbi Yochanan ben Nuri: dak means thin
The second view in the mishnah is that of Rebbi Yochanan ben Nuri, who rules "afilu aroch": even a long hair is included, since, as he puts it, "she'ein mashma'us dak ela rakik", the word dak in its plain sense means thin. What the Torah wants is a feeble, fine strand, a hair with no body to it, as the shampoo commercials would say nowadays. How long or short it happens to be makes no difference; the texture is everything.
His support is drawn from ordinary human speech. The mishnah has him ask "mah lashon omrim", how do people actually use the word? "Dak makel zeh, dak kaneh zeh": when someone calls a stick or a reed dak, nobody imagines he is telling us it is short. He is telling us it is thin. The same should hold for the hair of a nesek: dak points to fineness, and the hair may be either short or long.
Rebbi Akiva's answer
Rebbi Akiva does not accept the proof. He answers "ad she'ani lomed", rather than deriving the definition "min hakaneh", from a reed, "nilmad min hase'ar", let us derive it from hair, which is precisely the subject under discussion in the pasuk. When people call a person's hair dak, what they convey is dak lakui katzer, a hair cut short in length. They do not intend dak lakui aroch, a hair that is fine and yet long. How the word is employed with regard to hair is what should shape our reading of the pasuk.
The Rav concludes: "Vehalacha keRebbi Akiva." The halacha follows Rebbi Akiva, that se'ar tzahov dak means a golden hair that is short.
So our mishnah has given us both the framework of the nesek, two possible weeks of hesger and two simanei tumah, and the precise definition of the first of those simanim: two golden hairs, stunted and short, in a discolored patch of the scalp or the beard.