Reference for Bava Batra 106:3

בעי רבי אלעזר החזיק במצר לקנות שתיהן מהו מי אמרינן האי מצר אפסרא דארעא הוא וקני או דלמא האי לחודיה קאי והאי לחודיה קאי תיקו

This question must stand over. R. Eleazar put the question: Suppose he takes possession of the boundary with the idea of becoming owner of both fields, how do we decide? Do we say that the boundary is as it were the bridle of the land<span class="x" onmousemove="('comment',' If a man buys ten animals and takes hold of the bridle of one, he becomes the owner of all ten (Kid. 27b). If then we compare the boundary to a bridle, possession of it should confer ownership of both fields. ');">⁵</span>

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