2,590. Halacha vs. Halacha l'Maaseh

Hilchos Shechita 11:6

According to the law in this matter, if string-like adhesions were found hanging from the lung, whether they extended from the lung to the ribs, to the heart or to the diaphragm, we cut the adhesion, remove the lung, put it in warm water and inflate it. If it’s found to be punctured, the animal’s a treifa. If the water doesn’t bubble, the lung has no holes and the animal is permitted. This is because the adhesion wasn’t in the place of a puncture, or only the lung’s outer membrane was punctured. The Rambam notes, however, that he never saw anyone rule on such a case and he doesn’t know of any place that follows this halacha in practice.

Hilchos Shechita 11:7

While the previous halacha reflects how the Sages ruled, the common practice is to tear open an animal’s diaphragm to see if the lung in its proper place. If an adhesion isn’t found between the lobes and the flesh – neither on the flesh between the ribs nor on the flesh of the chest – or if an adhesion was found reaching from one lobe to another in order, or from the lung to the lobe next to it, the animal is permitted.