Reference for Bekhorot 58:18

אי שמעו ביה רבנן מפסדו לי מינאי:

And the first Tanna?<span class="x" onmousemove="('comment',' In our Mishnah, who forbids the purchasing of skins of both sexes, as he makes no distinction. But surely one can observe a difference in the skins!');">⁸</span>

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