Reference for Chullin 5:3

ואי בעית אימא

- It must be that he became unclean through contact with a [dead] reptile.<span class="x" onmousemove="('comment',' In this case the reptile is the primary source of uncleanness () ; the slaughterer by touching the reptile becomes unclean in the vtnuyk iuatr first degree () and cannot convey his uncleanness to the knife; for the rule is that anything which is unclean in the first degree can only defile foodstuffs or liquids but not other objects.');">³</span>

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