Reference for Chullin 154:18

אלא אי אתמר הכי אתמר א"ר אלעזר

There is [a Baraitha] taught in support of R'Eleazar's view,<span class="x" onmousemove="('comment',' That there is a distinction between an afterbirth that is attached to the foetus and one that is not so attached.');">⁹</span>

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