Nazir

Alternatively, [the number six] referred to members coming from a corpse, but it did not refer to [the case of] a member [severed] from a living being. Alternatively, [the number six] referred to all those [cases] where a nazirite must poll because of 'overshadowing' them, but excludes [the case of] a barley corn's bulk of bone,  since he need not. Alternatively, [the number six] referred to all those [cases] from which he retracted, but excludes [the case of] a quarter [log] of blood, from which he did not retract. For Rabbi said to Bar Kappara, 'Do not include [the case of] a quarter [-log] of blood amongst the retractions, for R. Akiba had that as a [traditional]  teaching, and furthermore the verse, Neither shall he go in to any dead body,  supports him. — R. Simeon says: All his life he declared [a quarter-log of blood from two corpses] unclean, whether he retracted after his death, I do not know.  — A Tanna taught that [R. Simeon's] teeth grew black because of his fasts. Come and hear: It has been taught: Beth Shammai say that a quarter [-kab] of bones, be they any of the bones, whether from two [limbs] or from three,  [is sufficient to cause defilement by overshadowing]. And Beth Hillel say, a quarter [-kab of bones] from a [single] corpse [is required], [and these bones must be derived] from [those bones which form] the greater part [of a skeleton] either in frame  or in number.  R. Joshua asserted: I can make the statements of Beth Shammai and Beth Hillel one.  For [when] Beth Shammai say 'from two [limbs] or from three,' [they mean] either from two shoulders and one thigh, or from two thighs and one shoulder, since this is the major part of a man's structure in height, whilst Beth Hillel say [the quarter kab must be taken] from the corpse, [viz.] from the greater part either in structure  or in number, for this [numerical majority] is to be found in the joints of the hands and feet.  Shammai says even a [single] bone, from the backbone or from the skull [defies by overshadowing]!  — Shammai is different, as he takes the more stringent view. Can one infer from this that Shammai's  reason is that he takes the stricter view, but the Rabbis would require both backbone and skull? — No! For the Rabbis may only disagree with Shammai concerning a single bone coming from the backbone or the skull, but where these are complete one alone [may be sufficient]. Rammi b. Hama propounded: What is the law in the case of a quarter [-kab] of bones [coming] from the backbone and the skull? When [our Mishnah] stated that a half-kab of bones [is required], was it only where there are present [bones] from its other limbs [too], but since [the bones] from the backbone and skull are treated more seriously, even a quarter [-kab] of bones [is sufficient], or perhaps there is no difference?  — Raba replied: Come and hear: [We learnt:] THE BACKBONE AND THE SKULL.  Now if you assume that a quarter [-kab] of bones coming from the backbone and the skull is to be taken more seriously,  it should state 'for a quarter [-kab] of bones coming from the backbone etc.'?  —