Chullin 45 - Who Is An Honest Sage?
Rav Chisda said: "Who is considered an honest Torah scholar? - One, who in a case of an equal doubt if his animal was slaughtered correctly or it became a terefah , decided that it was a terefah and bore the loss." About him the Psalms say, "When you eat the labor of your hands, happy are you and it will be well with you." Rav Zevid explained, "Happy are you in this world" - because he does not rely on the support of others. "It will be well with you" - in the World to Come - because he will stay away from theft, which would diminish his share in the World to Come.
If an animal's windpipe was perforated like a sieve, then if the flesh was merely moved to the side, the animal is kosher unless half of the windpipe was perforated; however, if the flesh in the perforations was missing, then once the holes combine to an area of an issar coin, the animal is terefah.
Further cases of terefah: if the membrane of the brain was punctured, and this means the lower membrane; or if the heart was punctured into its chamber.
Art: Justus Juncker - A Scholar Sitting At His Desk