Reference for Bava Kamma 78:8

ת"ר שור חרש שוטה וקטן שנגח רבי יעקב משלם ח"נ

that is, we do nothing to diminish its value, which would, of course, show that [Symmachus holds] no guardian is appointed in the case of <i>Tam</i> to collect payment out of its body. 'The Sages, however, say that a guardian should be appointed in whose presence evidence may be given', from which it follows that [they hold] a guardian may be appointed in the case of <i>Tam</i> to collect payment out of its body.

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