One who touches a zav, a zavah, a niddah, a woman who has given birth, a metzora, or a [midras-contaminated] couch or seat —- contaminates two and invalidates one. [Once he] separates, he contaminates one and invalidates one. [This ruling applies] equally [to] one who touches, one who moves, one who carries, and one who is carried.

One who touches the zav-fluid of a zav, or his saliva, or his semen, or his urine or [one who touches] the [menstrual] blood of a niddah —- contaminates two and invalidates one. [Once] he separates, he contaminates one and invalidates one. [This ruling applies] equally [to] one who touches and [to] one who moves. R’ Eliezer says: [Providing that] he carries [it].

One who carries the [contaminated] saddle [of a zav], or one who is carried upon it, or one who moves it contaminates two and invalidates one. [Once] he separates, he contaminates one and invalidates one.  One who carries an animal carcass, or purification water of an amount sufficient for sprinkling, contaminates two and invalidates one. [Once] he separates, he contaminates one and invalidates one.

One who eats of the carcass of a kosher bird, and [the flesh] is in his throat, contaminates two and invalidates one. If he in-serted his head into the airspace of an oven, [the oven is] tahor. If he spit it out, or swallowed it, he contaminates one and invalidates one. But while it is in his mouth, before he swallows it, he is tahor.