Reference for Bava Kamma 50:9
בגד ועור דכתב רחמנא בשרץ למה לי ש"מ לאפנויי
how can you draw an analogy to corpses where the minimum to cause uncleanness is not the size of a lentil but that of an olive?<span class="x" onmousemove="('comment',' Naz. 49b. ');"><sup>22</sup></span> — The <i>Gezerah shawah</i> must thus be 'free'. Is it not so? For indeed the law regarding dead reptiles is placed in juxtaposition to semen virile as written, <i>Or a man whose seed goeth from him</i>,<span class="x" onmousemove="('comment',' Lev. XXII, 4. ');"><sup>23</sup></span> and there immediately follows, <i>Or whosoever toucheth any creeping thing</i>. Now in the case of semen virile it is explicitly stated, <i>And every garment, and every skin, whereon is the seed of copulation</i>.<span class="x" onmousemove="('comment',' Ibid. XV, 17. ');"><sup>24</sup></span>