Reference for Niddah 112:63
<big><strong>גמ׳</strong></big>
ARE BELIEVED WHEN THEY DECLARE CONCERNING — A BEAST WHETHER IT HAD GIVEN BIRTH TO A FIRSTLING<span class="x" onmousemove="('comment',' So that the next birth is free from the restrictions imposed on a firstling. ');"><sup>53</sup></span> OR HAD NOT GIVEN BIRTH TO ONE. THEY<span class="x" onmousemove="('comment',' Samaritans. ');"><sup>52</sup></span> ARE BELIEVED WHEN GIVING INFORMATION ON THE MARKING OF GRAVES,<span class="x" onmousemove="('comment',' Sc. any place not so marked may be treated as clean. ');"><sup>54</sup></span> BUT THEY ARE NOT BELIEVED EITHER IN REGARD TO OVERHANGING BRANCHES,<span class="x" onmousemove="('comment',' This is explained in the Gemara infra. ');"><sup>55</sup></span> OR PROTRUDING STONES<span class="x" onmousemove="('comment',' This is explained in the Gemara infra. ');"><sup>55</sup></span> OR A BETH HA-PERAS.<span class="x" onmousemove="('comment',' This is explained in the Gemara infra. ');"><sup>55</sup></span> THIS IS THE GENERAL RULE: IN ANY MATTER WHERE THEY ARE UNDER SUSPICION THEY ARE NOT BELIEVED.