Niddah

R. Isaac b. Samuel b. Martha once sat at his studies before R. Kahana and in the course of the session he observed: Rab Judah citing Rab laid down that throughout the first three days  the placenta  is attributed to the child,  but henceforth the possibility of the birth of a second child  must be considered.  Said the other to him: But could Rab have said such a thing? Did not Rab in fact state, 'One child is not detained at all after the other [had been born]'?  The first remained silent. Said the other to him: Is it not possible that one statement  referred to an abortion, while the other  referred to a child that was viable? — You, the first  answered, have indeed stated Rab's actual rulings, for Rab has explicitly made the following statement: If a woman aborted an embryo and after that she aborted a placenta, if this occurred within three days  the placenta is attributed to the embryo, but if it occurred at any subsequent time the possibility of the abortion of a second embryo must be taken into consideration. If, however, she gave birth to a normal child and subsequently aborted a placenta, even if that occurred between that moment and ten days later,  the possibility of the abortion of a second child  need not be considered at all. Samuel and the disciples of Rab and Rab Judah  were once sitting at their studies when R. Joseph the son of R. Menashya of Dewil passed along in great haste. 'There comes towards us', he exclaimed, 'a man whom we can throw down with a piece of straw  and he would allow himself to be thrown down and pushed out'.  In the meanwhile he approached them. What, said Samuel to him, did Rab rule in regard to a placenta? — Thus, the other replied, said Rab: The placenta may be attributed only to a child that is viable.  Samuel then put the question to all the disciples of Rab and they told him the same thing. Thereupon he turned round and looked at Rab Judah with displeasure. R. Jose b. Saul enquired of Rabbi: What is the law where there was an abortion in the shape of a raven and [this was followed by] a placenta?  — The other replied: We can attribute a placenta only to an embryo in whose species  the placenta is [one of their organs].  What is the law where the placenta is tied to it?  — You, the other replied, have asked a question about that which does not exist. He raised an objection against him: If a woman aborted something in the shape of a beast, a wild animal or a bird, and a placenta with them, whenever the placenta is attached to it there is no need to take into consideration the possibility of the existence of a second embryo, but if no placenta is attached to it the possibility of the existence of a second embryo  must be considered, and one  must [impose on the woman] on account of them