3. [If] the water of a spring branched out, resembling a centipede, [and] one added to it and [thus] caused it to flow [further], it [remains] as it was. [But if] it was standing [water], and one added to it and [thus] caused it to flow, [then] it is equal to a mikveh in that it purifies [only] with still water, and [it is equal] to a spring in that one may immerse [things] therein whatever its amount.

4. All the seas are like a mikveh, as it is said: And the gathering [mikveh] of waters He called ‘‘seas’’; [these are] the words of R’ Meir. R’ Yehudah says: [Only] the Great Sea is like a mikveh, [and] it says seas only because it contains many kinds of seas. R’ Yose says: All the seas can purify while flowing, but they are unfit for zavim and for metzoraim and for consecrating therefrom purification water.

5. Flowing water is like a spring, and trickling water is like a mikveh. R’ Tzadok testified that when the flowing water is more than the trickling water, it is valid. And [if] trickling water was made to flow, it may be blocked even with a stick or even with a cane, [and] even by a zav or a zavah, and [then] one may go down and immerse oneself. [These are] the words of R’ Yehudah. R’ Yose says: One may not stop a flow with anything that is susceptible to tumah.

6. [If] a wave that became separated consisted of forty se’ah, and it fell on a person or on utensils, they become tahor. In any place that contains forty se’ah, one can immerse oneself and one can immerse [things]. [Hence,] one may immerse [things] in pits, or in ditches, or in a donkey track that is mingled in the countryside. Beis Shammai say: One may immerse [things] in a river that flows down a mountain. Beis Hillel say: One may not immerse [anything therein]. They agree [however] that one may make an enclosure with utensils and [then] immerse himself therein. But the utensils [themselves] used to make the enclosure are not [deemed as] immersed.