Niddah

The following was said by the Rabbis before R. Papa: But are all these answers  tenable? Was it not in fact taught, 'When they  issue they do so only while clinging to one another'?  — R. Papa replied: From this  it may be inferred that the embryo clings to the sandal at the middle of the latter  which lies across the head of the former.  Consequently, as regards the law of the firstborn, [the reference is to a case], for instance, where the embryo  issued with its head first  so that the sandal  issued first.  As regards the law concerning those punishable by kareth it is a case where they  issued with their feet first so that the embryo was born first.  R. Huna b. Tahlifa citing Raba explained: It may even be said that they  cling together side by side, but reverse the previous statement:  As regards the law of the firstborn [the reference is to a case] where they  issued with their feet first; so that the embryo, being animated hangs on and does not easily come out; while the sandal, not being animated, glides and comes speedily out. As regards the law concerning those subject to the penalty of kareth [the reference is to a case] where they issued with their heads first, so that the embryo, being animated is deemed to have consummated its birth as soon as its head came out; while the sandal [being inanimated cannot be deemed to have been born] until its greater part came out. MISHNAH. IF A PLACENTA IS WITHIN A HOUSE, THE HOUSE IS UNCLEAN;  NOT BECAUSE A PLACENTA IS A CHILD BUT BECAUSE GENERALLY THERE CAN BE NO PLACENTA WITHOUT A CHILD. R. SIMEON SAID, THE CHILD MIGHT HAVE BEEN MASHED  BEFORE IT CAME FORTH. GEMARA. Our Rabbis taught: The placenta in its first stage resembles a thread of the woof and in its final stage it resembles a lupine. It is hollow like a trumpet; and no placenta is smaller than a handbreadth. R. Simeon b. Gamaliel stated: The placenta resembles the craw of a hen  out of which the small bowels issue. R. Oshaia, the youngest of the fellowship,  taught:  Five things have a prescribed minimum of a handbreadth, and they are the following. A placenta, a shofar, a spine, a sukkah wall and a bundle of hyssop. As to the placenta there is the ruling just mentioned.  'Shofar'?  For it was taught: What must be the size of a shofar?  R. Simeon b. Gamaliel explained: It must be of such a size as can be held in one's hand and be seen at either end, viz.,  a handbreadth.  What is meant by 'spine'? The ruling which R. Parnak laid down in the name of R. Johanan: The spine of the lulab must be long enough to project a handbreadth above the myrtle.  'The Sukkah  wall'? As it was taught: Two walls  must be proper ones but the third is valid even if it is only one handbreadth wide. 'Hyssop'? As R. Hiyya taught: The bundle of hyssop  must be a handbreadth long. R. Hanina b. Papa stated: Shila of the village of Tamartha discoursed on three Baraithas and two reported traditions dealing with the prescribed size of a handbreadth. 'Two'  [you say]; is it not only one?  — Abaye replied, read:  R. Hiyya stated,  'The bundle of hyssop must be a handbreadth long'. But are there no others?  Is there not in fact [the law that an enclosed space of] one handbreadth square and one handbreadth in height, forming a cube  conveys uncleanness  and constitutes a screen  against uncleanness?  — We spoke of the size of 'a handbreadth'; we did not speak of 'a handbreadth square'. But is there not the law concerning a stone that projected one handbreadth from an oven  or three fingerbreadths from a double stove  in which case it serves as a connecting link?  We spoke only of cases where the size of less than a handbreadth is invalid, but here the law would apply all the more to such a case where the size is of less than a handbreadth and it is a handle of the oven. But is there not