Reference for Chullin 165:15

לעולם בזה אחר זה

[I reply that] in this case one was not as much as an olive's bulk.<span class="x" onmousemove="('comment',' The sciatic nerve of one animal was as much as an olive's bulk but not that of the other. (See Rashi.) According to R. Judah, therefore, he only incurs forty stripes. According to the Rabbis, however, if a man ate the entire sciatic nerve, even though in all it was not as much as an olive's bulk, being a distinct entity, he is liable. The Rabbis therefore hold that in the above case he incurs eighty stripes.');">⁶</span>

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