Reference for Chullin 144:18

לאו איתמר עלה אמר עולא

'If a piece of cloth three handbreadths square [that had contracted midras uncleanness]<span class="x" onmousemove="('comment',' I.e., a person suffering with a discharge from his body had put his full weight upon this cloth, e.g., by sitting or standing upon it or by leaning xrsn against it. Cf. Lev. xv, 4. And whatever has been thus rendered unclean by 'pressure', provided it was not less than three handbreadths square, will render unclean men and vessels.');">⁸</span>

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