Rambam - 1 Chapter a Day

I.e., if it gives birth successfully, that is a sign that it is intact. There is no need for an inspection or waiting twelve months. Even the Rama, who maintains that we are not knowledgeable with regard to inspections in the present age, will consider an animal acceptable if it lives this amount of time (Yoreh De’ ah 57:18).

Without informing him of the doubt involved.
The Rama quotes the Sha‘arei Dura who writes that if a condition that renders an animal treifah is obvious, we permit its sale to a gentile. For a Jew who seeks to purchase it will immediately become aware of the difficulty.
The Rama also mentions the ruling of the Terumat HaDeshen that if there is merely a question of whether an animal is treifah, it may be sold to a gentile. The Siftei Cohen 57:51 accepts this leniency only with regard to an animal regarding which there is a question whether or not it was attacked, but not with regard to other conditions.

Chullin 11 b explains that this is based on the principle that we follow the treifah. Since most animals are healthy we assume that this is an animal’s condition unless there is reason to suspect otherwise. Note, however, Halachah 7.

Based on Chullin 51a, the Kessef Mishneh goes further and states that even if the animal possesses a condition that is somewhat problematic, if we can find a commonplace explanation for it that will not render an animal treifah and the factor that will render it treifah is uncommon, we do not require an examination.

See Chapter 10, Halachah 4.

See Chapter 9, Halachah 1 7.

See Chapter 10, Halachah 7.

I.e., the strands and similarly, the other conditions the Rambam proceeds to mention, are abnormal factors that lead us to the supposition that there was a perforation in the lung. See Chapter 7, Halachot 5-11 that mention several situations of this nature.

The Ra’avad objects to the Rambam’s ruling, maintaining that even if the swelling is an indication that the bronchiole has been perforated, that does not disqualify the animal, for it is possible that it is sealed by flesh. The Radbaz explains that the Rambam would also accept that ruling and one of the points that one must inspect is whether there is flesh under the swelling or not.

See Chapter 7, Halachah 8. As mentioned in the notes to that halachah, there is a difference of opinion among the Rishonim concerning this issue.
The Ra’avad also mentions that the Rambam’s ruling here appears to contradict his ruling in Chapter 7, Halachah 5. For there, the Rambam differentiates between whether or not there is a bruise on the chest, and there he does not speak of inspecting the lung in warm water. In a lengthy discussion in his gloss to Chapter 7, the Kessef Mishneh explains that there is no contradiction between the two rulings.

I.e., if the water bubbles.

There is a difference of opinion among the halachic authorities if this situation is possible or not.

I.e., as the Rambam proceeds to explain in the following halachah, the common custom is more stringent.

See the Shulchan Aruch (Yoreh De’ah 39:1) which states that we must check the lungs for sirchot and concludes: “Whoever breaks ranks and eats without checking [the lung] should be bitten by a snake.”

For as stated in Chapter 7, Halachot 3-4, even a perforation found in this place does not render the animal treifah.

For as stated in Chapter 8, Halachah 5, an adhesion of such a type does not render the animal treifah.

See the notes to Halachah 9. Depending on the version of that text, the Rambam’ s ruling concerning this matter may be questioned.

The Rama (Yoreh De’ah 39:18) writes that it is common custom in the Ashkenazic community to rule that all sirchot in the lung cause an animal to be deemed forbidden except those extending from a lobe to the lobe next to it or those from the body of the lung to the lobe next to it. He does, however, permit leniency if it is possible to rub out the sirchah and then examine it to see that there is no perforation.

I.e., except to the lobe that is near it (Radbaz).

See Chapter 8, Halachah 1, which explains that this is a tiny lobe found on the right side of the lung.

For we fear that it will cause a perforation in the lung. See the gloss of the Radbaz to Halachah 6.

The text of the Mishneh Torah which the Ra’avad had seemed to imply that even a strand extending from the body of the lung to the lobe is unacceptable. The Ra’avad therefore protests and maintains it is acceptable. The Migdal Oz states that he also saw texts of the Mishneh Torah with this version, but that the authoritative manuscripts do not follow that reading. This is also the position of the Kessef Mishneh.

If the sirchah is attached to the flesh alone, it does not cause an animal to be considered treifah (see Chapter 7, Halachah 4). Here, however, it is attached to both the flesh and the bone and that creates the problem.

The Shulchan Aruch (Yoreh De’ah 39:18) cites the Rambam’s position.
Parenthetically, the commentaries have questioned the Rambam’ s statements here from the standpoint of kibud av, “honoring one’s father.” Seemingly, after mentioning his father, he should have stated - as he himself rules in Hilchot Mamrim 6:5 - “May he be remembered for the life of the world to come.” Also, that same source (Halachah 3) forbids “offering an opinion that outweighs [that of his father].”

The Ra’avad follows the more lenient view. Here also the Shulchan Aruch (loc. cit.) cites the Rambam’s position.

The Rama (Yoreh De’ah 39:1) mentions both the custom of inflating the lung in all cases and the Rambam’s position that it is not necessary to inflating all lungs. He concludes that the Rambam’s position should be given primacy.

I.e., the stringencies forbidding an animal because of certain sirchot and requiring the lungs to be blown up.

Halachot 6 and 7.

At present, there are certain Rabbinic authorities who require that the lungs of a chicken be inspected, because in the present age, since chickens are raised in a manner very different from their natural circumstances, it ·is common for there to be difficulties with regard to their lungs.

If there is no evidence that a factor existed that caused the animal to become treifah, we do not assume that one existed. Even according to the custom that requires an animal to be checked, we are assuming only the possibility that it might have a disqualifying factor. If there is no way to check it, we assume that the animal is kosher.
The Ra’avad differs and maintains that since disqualifying factors involving the lung are common, if a lung was not inspected, we cannot consider the animal as kosher. The Shulchan Aruch (Yoreh De ‘ah 39:2) quotes the Rambam’s view. The Rama mentions the position of the Ra’avad and states that the Rambam’s position may be followed only when there is a possibility of severe financial loss.

Normally, we would not inflate a lung unless there was a factor that aroused suspicion. Nevertheless, in this instance, since we did not see it in its natural situation - and the possibility exists that there were such factors - we require an examination. The Turei Zahav 39:2 states that, according to our custom [see Rama (Yoreh De’ah 39:4)] that we do not rely on an examination when there is a clearly problematic situation, we do not rely on an examination in this instance as well.

The Shulchan Aruch (Yoreh De’ah 39:8) rules that such an animal is permitted without the lung being inspected. The Turei Zahav 39:12 states that an examination must be conducted to see whether the lung is perforated or not.
This represents the difference between glatt meat and meat that is not glatt. Glatt means “smooth,” i.e., there are no sirchot, adhesions, or growths, extending from the animal’s lungs. Thus there is no need to inspect it. When meat is not glatt, there were sirchot and/or the like extending from the lungs. They were inspected and no perforation was discovered. Hence, the meat is kosher. Nevertheless, there are many who follow the stringency of not partaking of it.
(It must be emphasized that, at present, glatt is sometimes used as a general term to connote a higher level of punctilious observance of the details of kashrus in general without specifically referring to questions concerning the lungs.)