Reference for Chullin 70:28

וכי הדם מכשיר

Come and hear: [We have learnt:] R'Simeon says: The blood of a dead [animal]<span class="x" onmousemove="('comment',' Which died a natural death (Rashi) . Tosaf. suggests that it refers to the blood of a human corpse.');">¹⁰</span>

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