Reference for Yevamot 151:5
אלא אמר אביי מעברינן קמיה בגדי צבעונין אמר רבא אטו כ"ע ברזילי הגלעדי הוא אלא מחוורתא כדשנין מעיקרא
Our Rabbis taught: If it<span class="x" onmousemove="('comment',' The duct of the semen. ');"><sup>9</sup></span> was punctured [the man is regarded as] unfit, because the flow is sluggish.<span class="x" onmousemove="('comment',' And does not fertilize. ');"><sup>10</sup></span> If it was closed up [he is deemed to be] fit, because he is then capable of production. And this is a case where the unfit may return to his former state of fitness. What does the expression 'this' exclude? — It excludes the case where a membrane was formed on the lungs in consequence of a wound; since such cannot be regarded as a proper membrane.<span class="x" onmousemove="('comment',' It may easily burst. The lungs are, therefore, regarded as wounded, and the animal from which they were taken is unfit for consumption. Cf. Hul. 42a. ');"><sup>11</sup></span>