Niddah

BECAUSE THEY MAINTAIN: IT IS POSSIBLE etc. What need again was there for this statement, seeing that it was already taught in the earlier clause? And were you to reply: Because it was desired to lay down an anonymous statement  in agreement with the Rabbis [it could be objected:] Is not this obvious, since in a dispute between an individual authority and a number of authorities the halachah is in agreement with the majority? — It might have been presumed that R. Meir's reason is more acceptable because Scriptural texts  provide support for his view, hence we were informed  [that the halachah is in agreement with the view of the Rabbis]. And if you prefer I might reply: Because it was desired to state,  'Similarly'. MISHNAH. SIMILARLY  ANY [HOLE IN] AN EARTHEN VESSEL THAT LETS IN A LIQUID  WILL  LET IT OUT,  BUT THERE MAY BE ONE THAT WILL LET IT OUT AND WILL NOT LET IT IN.  ANY LIMB  THAT GROWS A NAIL HAS ALSO A BONE IN IT  BUT THERE MAY BE ONE THAT HAS A BONE IN IT BUT GROWS NO NAIL.  WHATEVER CONTRACTS MIDRAS-UNCLEANNESS  ALSO CONTRACTS CORPSE-UNCLEANNESS  BUT THERE ARE SUCH AS CONTRACT CORPSE UNCLEANNESS  AND DO NOT CONTRACT MIDRAS-UNCLEANNESS. GEMARA. A vessel with a hole THAT LETS IN A LIQUID is unfit for the water of purification  and is [even more so] unfit  as a defective vessel;  one with a hole THAT WILL LET IT OUT  is fit for the water of purification  but unfit as a defective vessel. R. Assi stated, It was learnt,  The minimum size [of a hole to render] an earthen vessel [unfit for the consecration of the water of purification] is one that will let a liquid in;  and one that will let a liquid out  was mentioned only in respect of a defective vessel.  What is the reason?  — Mar Zutra son of R. Nahman replied: Because people do not say,  'Bring a defective vessel for another defective vessel'. Our Rabbis taught: How is an earthen vessel to be tested in order to ascertain whether its perforation is big enough to admit a liquid or not? One brings a tub full of water and puts the pot  into it. If it absorbs any of the liquid, it may be taken for granted that it lets liquids in; and if not, it may be taken for granted that it only lets liquids out.