Menachot 24b (כד:) — the Talmud in English

And didn’t we learn in the Mishna: A sheet

that is

impure

with midras impurity,

having become impure when a zav lay upon it, thereby becoming a primary source of impurity that renders a person impure,

and

afterward

made it

into a sheet that would serve as a

curtain—

the sheet is pure

from

the

impurity of

the midras!

Since it is no longer designated for lying upon, and anything that is not designated for midras impurity does not become impure with midras impurity,

but it is impure

with a lesser impurity, which renders neither a person nor anything else impure, but only food or liquids, in accordance with the law of

“contact with midras,”

as the sheet has the status of a vessel that came into contact with midras, which renders only food and liquids impure. 108 .

Rabbi Yosei said: And with what midras did

the sheet

in question come into contact?

If so, why should the impurity of contact with midras remain upon it? It is not possible to say that after the sheet is made into a curtain it acquires contact impurity,

but

only in a case

where the zav touched it

while lying upon the sheet [the lying of a zav that renders an object impure with midras can occur even without the zav touching the sheet, for example, if an intervening object separates them], and the sheet became impure with two types of impurity, the midras impurity of the zav and the impurity resulting from contact with the zav. After it was made into a curtain and its status as midras was revoked, it became pure from midras impurity, but it remained

impure

with a lesser impurity due to

contact with the zav,

since this impurity applies not only to an object designated for lying upon and is not removed when the sheet is made into a curtain.

Abaye concludes his question to Rava:

At least, when the zav touched it—

it is impure

through contact with a zav,

even

if the contact occurred

at the end,

after the zav had lain upon it and it had already become impure through midras!

And why

does the impurity of contact take effect upon the sheet?

Let us say

that

it has had its fill of

the sheet’s

impurity

of midras and can no longer receive an additional impurity!? Rather, it is certainly evident that we do not say, “It has had its fill of impurity,” and if so, there is no basis for Rava’s uncertainty?

Rava said to him,

Rava said:

And from where do you know that this statement, “if the zav touched it

it is impure through contact,” which Rabbi Yosei stated, refers to a case in which he touched it

after

it had already become impure with

midras

impurity?

Perhaps

the contact occurred

before

it became impure with

midras

impurity, and afterward the zav pressed upon it. Therefore, we do not say, “It has had its fill of impurity,” because

it was

the midras impurity

a severe impurity

that can take effect

upon a lesser impurity

of contact with a zav.

But here,

in the case of the half-issaron, it is speaking of a case in which it had already become impure and afterward one who had immersed that day touched it.

For both this and that—

the two impurities—

are lesser impurities.

Therefore there is room to entertain the possibility that

the second

impurity does not take effect after it has had its fill from the first impurity.