Reference for Bekhorot 50:40

שדה שאבד בה קבר נכנס בתוכה טמא

But R'Assi says: The difference of opinion relates to a case where he searched and found [a blemished animal],<span class="x" onmousemove="('comment',' For we fear, according to the first Tanna quoted above, lest the blemished animal found was really another, and, therefore, all the animals require examination, whereas R. Jose maintains that making a search is adequate and, having discovered a blemished animal, we presume that it is the one which became mixed up with the rest.');">²⁰</span>

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