Niddah

AND THE FLESH OF A CORPSE. Whence is this deduced? — Resh Lakish replied: Scripture said, Whatsoever uncleanness he hath,  implying all forms of uncleanness  that emanate from him.  R. Johanan replied: Or a bone of a man, or a grave,  'a man' is  on a par with 'a bone'; as a bone [conveys uncleanness when] dry so does a man.  What is the practical difference between them?  — The practical difference between them is the case of flesh that  crumbles. An objection was raised: The flesh of a corpse that was crumbled is clean?  — There it is a case where it was pulverised and turned into dust. An objection was raised:  Every part of a corpse conveys uncleanness except the teeth, the hair and the nails, but while they are attached [to the corpse] they are all unclean?  — R. Adda b. Ahabah replied: It  must be exactly like a bone; as a bone was created simultaneously with it  so must every other part  be such as was created with it.  But are there not the hair and nails that were created with it  and they are nevertheless clean? — Rather, said R. Adda b. Ahabah, It  must be exactly like a bone; as a bone was created simultaneously with it  and when cut  does not grow again  so must every other part  be such as was created with it and when cut  does not grow again. The teeth are, therefore, excluded since they were not created with it,  and the hair and nails were excluded since, though they were created with it, they  grow again. But skin surely [is a part of the body] that  grows again, for  we have learnt: A skinned animal,  R. Meir declares, is ritually fit,  and only the Sages declare it to be unfit.  And even the Rabbis declare it to be unfit only because in the meantime  the air affects it and it would die, but the skin  would, as a matter of fact, grow again;  and yet have we not learnt: In the case of the following their skins are on a par with their flesh,  viz., the skin of a human being?  — Surely in connection with this ruling it was stated: 'Ulla said, 'Pentateuchally the skin of a human being is clean, and what is the reason why they ruled it to be unclean? It is a preventive measure against the possibility that a person might use the skins of his father and mother as spreads for an ass.' Others there are who read: Skin, surely, [is a part of the body] that  does not grow again, for  we have learnt: And the Sages declare it to be unfit.  And even R. Meir declares it to be fit only because its flesh hardens and the animal recovers its health but it does not, as a matter of fact, grow again,  and yet did not 'Ulla state, 'Pentateuchally the skin of a man is clean'? — When 'Ulla's statement was made it had reference to the final clause  only: But all these,  if they were dressed or trodden upon sufficiently to render them fit for dressing, are clean  with the exception of a human skin.  And it was in connection with this ruling that 'Ulla stated, 'Pentateuchally the human skin is clean if it had been dressed; and what is the reason why they ruled it to be unclean? It is a preventive measure against the possibility that a person might use the skins of his father and mother as spreads'. But does not flesh grow again and yet it is unclean? — Mar son of R. Ashi replied: The place of missing flesh becomes a scar. BUT THE ISSUE. Whence is this  deduced? — It was taught: His issue is unclean,  teaches concerning an issue of a zab that it is unclean.  But cannot this be arrived at by a process of reasoning: If it  causes uncleanness to others  would it not, with more reason, cause uncleanness to itself?  The case of the scapegoat proves the contrary, since it causes uncleanness to others  while it is itself clean. You also should not, therefore, be surprised in this case  where, though the issue carries uncleanness to others,  it is itself  clean. Hence it was specifically stated, 'His issue is unclean'  teaching thereby that the issue is unclean. But might it not be suggested that this  applies only to contact [uncleanness] but not to carriage, this being a case similar to that of a dead creeping thing?  — R. Bibi b. Abaye replied: There was no need for a Scriptural text as far as contact is concerned, since it  is not inferior  to semen,