A zav contaminates a couch in [one of] five ways, [rendering the couch able] to con-taminate a man to contaminate [his] clothing: [by the zav] standing [on it], sitting [on it], lying [on it], hanging [on it], or leaning [on it].   The [contaminated] couch [of a zav] contaminates a man in [one of] seven ways to [the degree that the man will further] contaminate [his] clothing: [by the man] standing [on it], sitting [on it], lying [on it], hanging [on it], or leaning [on it], [and] through contact, and through carrying.

[If] a zav and a tahor [person] sat [together] in a boat or a raft, or rode [together] on an animal, even though their clothes do not touch, the [clothes of the tahor person] become contaminated with midras tumah.  [If] they sat [together] on a board, on a bench, on the support beam of a bed or on a pole that are unsteady; [if] they [both] climbed up a weak tree, [or onto] a weak branch of a strong tree, [or onto] an Egyptian ladder that is not anchored with a nail; [if they went together] onto a ramp, a beam or a door that are not secured with plaster; [in all of these cases,] they become tamei. R’ Yehudah rules [them] tahor.

[If, together, a zav and a tahor person] close [a door] or open [a door, tumah is transmitted]. But the Sages say: Only when one closes [the door] and one opens [it, will tumah be transmitted].  [If] one raises the other from a pit [either way, tumah is transmitted]. But R’ Yehudah says: Only when the tahor person raises the zav [will tumah be transmitted].  [If, together,] they twist ropes [tumah is transmitted]. But the Sages say: Only when one pulls this way, and the other pulls that way [will tumah be transmitted].  [If, together,] they weave, whether [they do so] standing or sitting; or [if, together,] they grind [grain, tumah is transmitted]. R’ Shimon rules all of these tahor, except when they grind [together] with a hand grinder.  [If, together,] they unload a donkey or load a donkey —- when the load is heavy, they become tamei. When the load is light, they remain tahor. [However,] in all cases, they remain tahor [with regard] to [their status as] common people; they are [on-ly deemed] tamei [with regard] to [their permissibility to eat] terumah.

[If] a zav and a tahor [person] sat [together] in a large boat —- [and] which [boat] is [considered] a “large boat”? R’ Yehudah says: Any [boat] that cannot be swayed by a man —- [or if] they sat [together] on a board, on a bench, on the support beam of a bed, or on a pole that are not unsteady, [or if] they climbed up a strong tree, [or] a strong branch, or a Tyrean ladder, or an Egyptian [ladder] that is anchored with a nail; [or if they went together] onto a ramp, a beam, or a door that are secured with plaster, even if only from one side, [in all these cases] they remain tahor.  [If] the tahor person strikes the tamei [zav], he remains tahor. [However, if] the tamei [zav], strikes the tahor person, [the tahor person] becomes tamei, for if the tahor person would pull away, the tamei [zav] would fall down.