All objects that defile by overshadowing which were divided and then brought into a house: Rabbi Dosa ben Harkinas declares clean. But the sages declare [it] unclean. What is the case? One who touches two pieces of nevelah, each the size of half an olive, or carries them, Or, in the case of a corpse, if he touches a piece the size of half an olive and overshadows [another piece] the size of half an olive, Or if he touches [a piece] the size of half an olive and [another piece] the size of half an olive overshadows him, Or if he overshadows two [pieces, each] the size of half an olive, Or if he overshadows [a piece] the size of half an olive and [another piece] the size of half an olive overshadows him: Rabbi Dosa ben Harkinas declares him clean, And the sages declare him unclean. But if he touches [a piece] the size of half an olive and another object overshadows him and [another piece] the size of half an olive, Or if he overshadows [a piece] the size of half an olive and another object overshadows him and [another piece] the size of half an olive, he is clean. Rabbi Meir says: Even here Rabbi Dosa ben Harkinas declares him clean and the sages declare him unclean. Every [case] is unclean except [a case of] contact [combined] with carriage or of carriage [combined] with overshadowing. This is the general principle: every object [whose defilement] proceeds from one cause is unclean, from two causes is clean.

If a ladleful of corpse-mold was scattered about in a house, the house is unclean But Rabbi Shimon declares it clean. If a quarter [of a log] of blood was absorbed in [the ground] of a house, the house is clean. If it was absorbed by a garment: if the garment is washed and a quarter [of a log] of blood emerges from it, it is unclean, if not, it is clean, since anything absorbed that cannot emerge is clean.

[Blood] which was poured out in the air: If the place [where it fell] was an incline and [a person or vessel] overshadowed part of it, he [remains] clean. If it was a cavity, or if the blood congealed, he [becomes] unclean. If it was poured out on a threshold: If it inclined either inwards or outwards and the house overshadowed it [that which is in the house] is clean. If there was a cavity, or if it congealed, [that which is in the house becomes] unclean. Every part of a corpse is unclean except the teeth, hair and nails; But when they are joined [to the corpse], they are all unclean.

What is ‘mixed blood? The blood of a corpse of which an eighth [of a log] came out during his lifetime and an eighth after death, the words of Rabbi Akiva. Rabbi Ishmael says: a quarter [of a log] during his lifetime and a quarter after death. [If] a quarter [of a log] is taken from both of these: Rabbi Elazar bar Judah says: both of these are as water. What then is ‘mixed blood’? It is that of a crucified person whose blood is streaming forth and under whom is found a quarter [of a log] of blood it is unclean. However a corpse whose blood drips forth and under whom is found a quarter [of a log] of blood, [the blood] is clean. Rabbi Judah says: not so, but that which streams forth is clean and that which drips forth is unclean.

For an olive-sized portion of a corpse, an opening [in the room in which it is found] of one handbreadth [square], and for a [whole] corpse, an opening of four handbreadths [square, is enough] to prevent the uncleanness from [spreading to the other] openings; But for allowing the uncleanness to go out, an opening of one handbreadth [square is enough]. [A portion] greater than the size of an olive is as a [whole] corpse. Rabbi Yose says: [only] the spine and the skull are as a [whole] corpse.

[An object] one handbreadth square and one handbreadth high conveys uncleanness and blocks uncleanness. How does it [block uncleanness]? In the case of a covered drain beneath a house, if it has a space a handbreadth wide and its outlet was a handbreadth wide, and there is uncleanness inside it, the house remains clean; And when there is uncleanness in the house, that which is within [the drain] remains clean, for the manner of the uncleanness is to go out and not to go in. If it had a space one handbreadth wide but its outlet was not one handbreadth wide, when there is uncleanness in it, the house becomes unclean; But when there is uncleanness in the house, that which is within it remains clean, for the manner of the uncleanness is to go out and not to go in. If it did not have a space one handbreadth wide and its outlet was not one handbreadth wide, when there is uncleanness within it, the house becomes unclean; And when there is uncleanness in the house, it [also] becomes unclean. It makes no difference if the cavity was carved out by water or by a sheretz or if it had been eaten out by salt. And similarly [if it is in] a row of stones or a pile of beams. Rabbi Judah says: any "tent" not made by a person is not considered a tent’. But he agrees that crevices and crags [can be considered as ‘tents’].