Reference for Bava Metzia 155:8

אמרי דבי ר' ינאי רישא שמתה מחמת אויר דאמרינן אוירא דהר קטלה ואמרינן אוירא דבקעה קטלה ר' יוסי בר חנינא אמר כגון שמתה מחמת אובצנא רבה אמר כגון שהכישה נחש

BUT IF IT PERISHES OR IS INJURED, HE [THE OWNER] MUST SUPPLY HIM WITH A SUBSTITUTE. <b><i>GEMARA</i></b>. Why is no distinction drawn in the first clause [between the causes of death], whilst it is in the second? — The School of R. Jannai said: In the first clause it means that it died on account of the air, and so we say, The mountain air killed it, [or] the air of the plain killed it.<span class="x" onmousemove="('comment',' I.e., the climate of either of these places did not suit it. ');">¹⁴</span>

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