Reference for Chullin 67:20

טומאה משיעורין לא גמרינן

He [R'Eliezer] retorted, [Yes] but that liqui also becomes unclean in the first degree.<span class="x" onmousemove="('comment',' So that according to your argument one who eats that which is unclean in the second degree should become unclean in the first degree! Of course R. Joshua never intended to make any inference from the liquid in that case, for he concedes that liquids are exceptional as they so readily contract uncleanness, but only from the foodstuff. (Rashi) . V. however Tosaf. ad loc.');">⁹</span>

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