הלכות טומאת מת

There are three conditions that protect an entity located under the same ohel as a corpse from contracting impurity: a sealed covering, an ohel, and the fact that something was swallowed. Being swallowed prevents pure entities from contracting impurity and prevents impurity that was swallowed from departing and spreading that impurity. In contrast, a sealed cover and an ohel prevent pure entities from contracting impurity, but they do not prevent the impurity from departing and causing other entities to become impure.
What is implied? If there is a container that is sealed in a house that is impure, everything in the container is pure. Similarly, if there is an ohel in such a house, all of the keilim in that ohel are pure. If, however, there was an olive-sized portion from a corpse placed in containers that were sealed close and then they were brought into a house, the house is impure. Similarly, if there was one ohel inside another ohel and an olive-sized portion of a corpse in the inner ohel, all of the keilim in the outer ohel are impure.

In contrast, when entities are swallowed, pure articles are prevented from contracting impurity and impurity is prevented from spreading.
What is implied? When a dog ate the flesh of a human corpse and entered a house, the house is pure. When a ring was swallowed, even by a person, and then the person who swallowed it entered an ohel where a corpse was located, even though the person contracts the impurity that lasts seven days, the ring remains pure. Similarly, the fact that an entity was swallowed by a beast, a domesticated animal, a fowl, or a fish prevents it from contracting impurity as long as they are alive. If, however, they die and the flesh of a human corpse or keilim are in their intestines, it is as if these articles were not swallowed.

If the majority of one of a fowl's determining signs for ritual slaughter was slit or the majority of both an animal's signs were slit, even though the living beings were still in their death throes, they are considered as dead. They no longer protect the keilim that are swallowed in their intestines, nor do they prevent impurity that is in their intestines from spreading outward and imparting impurity.

How long may the impurity remain in their intestines and still impart impurity when they die? For a dog three full days, i.e., three twenty-four hour periods. For other wild beasts, domesticated animals, fowl, or fish, one full day.
When does the above apply? When the flesh of the corpse remains in their intestines. If, however, a wolf swallows a baby and then expels it through its anus, the flesh is pure, but the bones are impure.

Entities that are swallowed are protected from impurity only in the digestive organs of a living creature, as we explained. Those, however, which are concealed in the body of a k'li or a stone are not protected.
What is implied? If there is a spindle in which a metal hook was concealed, into which the iron point was driven, or a brick in which a ring was found that were brought into an ohel in which a corpse was found, the articles are impure even though they are not visible and they are covered. The rationale is that articles encompassed by keilim are protected from impurity only by a sealed cover.
Similarly, if there was a pin or a ring covered in the clay used to reinforce an oven and the oven became impure because it was in an ohel where a corpse was located or a dead crawling animal fell into its inner space, the keilim in the clay become impure. If, however, the oven was sealed close, since the oven itself is pure, the keilim that are covered up by the clay on top of it are also pure.
Similarly, if a jug is sealed closed and there is a needle or a ring in the clay sealing at its side, they are impure, and they are not saved in an ohel where a corpse was located. If they were in the sealing of the jug over its opening and they could be seen from the inside of the jug, but do not enter its inner space, they are pure. If they enter its inner space, they are impure. The rationale is that an earthenware container that is sealed close does not protect the keilim that are inside of it, as will be explained. If there is a layer of clay, even as thin as a garlic shell under them, they are pure, even though they project into the inner space of the jug.

All keilim that are embedded in the earth of a house are impure and they are not protected. The rationale is that the earth of an ohel has the same status of the ohel itself until the very depths of the earth. This does not apply with regard to its walls, as will be explained.
What is implied? If there is impurity in a house and there are keilim embedded in its earth, even if they are deeper than 100 cubits, they are impure. If, however, there is a handbreadth by a handbreadth by a handbreadth of empty space in their place, they are pure, because it is as if they are in another ohel. To what can the matter be compared? To a loft that is built over a house. If there is impurity in the loft, the house is pure.
Similarly, if one divided a house with a partition that runs parallel to the ground and there was impurity between the partition and the earth, the keilim that are in the house above the partition are impure, because an ohel does not prevent the spread of impurity, as we explained. If there was impurity above the partition, the keilim between the partition and the earth are pure, because the ohel protects them. If there is not a space of a handbreadth between the partition and the ground, the keilim are considered as if they are embedded in the earth of the house and they are impure.

The following laws apply when there is a covered drain extending under a house and the drain is a handbreadth by a handbreadth by a handbreadth and its opening outside the house is a cubic handbreadth in size. If there is impurity in the drainage channel, the house is pure. If there is impurity in the house, the contents of the drainage channel are pure.
If the drain was a cubic handbreadth in size, but its opening on the outside was not a cubic handbreadth in size and there was impurity in it, the house is impure. If there is impurity in the house, the contents of the drainage channel are pure. The rationale is that it is not the way of impurity to enter a secondary entity like a drain.
If the drain was not a cubic handbreadth in size and its opening on the outside was not a cubic handbreadth in size and there was impurity in it, the house is impure. It is as if the impurity is in the house. If there is impurity in the house, the contents of the drain are impure. The rationale is that they are considered like keilim buried in the earth and the earth of a house has the same status as the house itself until the very depths.

When there are two jugs, each containing half of an olive-sized portion of a corpse and each is sealed close, placed within a house, they are pure, because a partial measure of impurity does not impart impurity. The house is impure, because there is an olive-sized portion of a corpse in the house and a sealed cover does not prevent the spread of impurity outward. The jugs do not become impure because of the house, because they are sealed close. If one of the jugs are open, it and the house are impure and the other jug is pure.
Similarly, if there are two rooms open to each other and to the main room of a house and there is half of an olive-sized portion of a corpse in the inner room or the middle room and half of an olive-sized portion of a corpse in the outer room, the outer room is impure. The inner room and the middle room are pure. If there is half of an olive-sized portion of a corpse in the inner room and half of an olive-sized portion of a corpse in the middle room, the inner room is pure. The middle and the outer rooms are impure, because it is the way of impurity to depart and not to enter.