Reference for Bava Metzia 19:19

כיון דנפל גלי דעתיה דבנפילה ניחא ליה דנקני בארבע אמות לא ניחא ליה דנקני

— [it is because our Mishnah deals with a case] in which he said, 'Give me it,' and did not say, 'Acquire it for me.'<span class="x" onmousemove="('comment',' Had the rider said: 'Acquire it for me by picking it up on my behalf' the object would have belonged to the rider. By saying: 'Give it to me,' the rider made it clear that the found object was to become his only when it was handed over to him. The other person is therefore entitled to keep the object. ');">¹⁹</span> <b><i>MISHNAH</i></b>. IF ONE SEES AN OWNERLESS OBJECT AND FALLS UPON IT, AND ANOTHER PERSON COMES AND SEIZES IT, HE WHO HAS SEIZED IT IS ENTITLED TO ITS POSSESSION. <b><i>GEMARA</i></b>. Resh Lakish said in the name of Abba Kohen Bardala: A man's four cubits acquire [property] for him everywhere. For what reason? — The Rabbis instituted [this law] in order that people might not be led to quarrelling. Abaye said: R. Hiyya b. Joseph raised an objection from [the tractate of] <i>Pe'ah</i>. Raba said: R. Jacob b. Idi raised an objection from the [tractate of] Nezikin.<span class="x" onmousemove="('comment',' The three 'Babas' ('Gates': Baba Kamma, Bava Metzia, and Baba Bathra), formed originally one tractate, which was called 'Nezikin'. ');">²⁰</span> Abaye said: R. Hiyya b. Joseph raised an objection from [the tractate of] <i>Pe'ah</i>:<span class="x" onmousemove="('comment',' Ch. IV, Mishnah 3. ');">²¹</span> If he [a poor man] takes part [of the gleanings] of the corner [of a field] and throws it over the rest [of the gleanings],<span class="x" onmousemove="('comment',' In order to acquire it by this act. ');">²²</span> he cannot claim anything. If he falls Upon it, [or if] he spreads his garment upon it, he may be removed from it. And the same [law applies] to a forgotten sheaf.<span class="x" onmousemove="('comment',' V. Deut. XXIV, 19. ');">²³</span> Now if you say that a man's four cubits acquire [property] for him everywhere, let the four cubits [of the poor man] acquire for him [the gleanings on which he fell]! — Here we deal with a case where the man did not say. 'I wish to acquire it.' But if the Rabbis instituted [this law], what does it matter if he did not say, ['I wish to acquire it']? — Since he fell [upon it], he made it clear that he wished to acquire it by falling [upon it]<span class="x" onmousemove="('comment',' He preferred to acquire the gleanings by the act of falling upon them, believing that this would be legally more effective than the claims of the four cubits sanctioned by the Rabbis, And as he did not intend to exercise the right afforded him as regards the four cubits, the right lapsed, and there was nothing in his action of throwing himself upon the gleanings to entitle him to claim their possession. ');">²⁴</span> but did not wish to acquire it by means of [his four cubits].

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