Bava Batra 321:1

מחק פסול ואע"פ שמקוים

an erasure [however] is inadmissible<span class="x" onmousemove="('comment',' Any writing on the spot erased is invalid. ');">¹</span> although it had been confirmed.<span class="x" onmousemove="('comment',' Because it is possible that the formula, 'firm and established', had been erased from its original position and re-written after the spurious matter that had been inserted in its place. Since an erasure of the formula would, thus, invalidate the added matter, there is no cause to apprehend any forgery, though the witnesses sign on the external side of the deed. ');">²</span>

ולא אמרו מחק פסול אלא במקום שריר וקיים וכשיעור שריר וקיים

[The law,] however, [that] an erasure invalid only applies<span class="x" onmousemove="('comment',' Lit., 'they only said'. ');">³</span> [to the case where it occurs] in the position [of the formula] 'firm and established'<span class="x" onmousemove="('comment',' At the end of the original text of the deed. ');">⁴</span>

ולר' ירמיה בר אבא דאמר אחורי הכתב וכנגד הכתב מבחוץ ליחוש דלמא כתיב מגואי מאי דבעי ומחתים סהדי יתירי מאבראי ואמר אנא לרבות בעדים הוא דעבדי

and [occupies the] same space as 'firm and established'.<span class="x" onmousemove="('comment',' Or more. ');">⁵</span> According to R. Jeremiah b. Abba, however, who stated, '[On] the back of the writing and corresponding to [all] the written part, on the external [side of the deed]',<span class="x" onmousemove="('comment',' And, since the signatures cover the entire extent of the writing, the end of the deed is clearly indicated; and the formula, 'firm and established', is not required at the foot of the deed. ');">⁶</span>

א"ל מי סברת עדים כסדרן חתימי עדים ממטה למעלה חתימי

is [there no cause] to apprehend that he might write on the inside<span class="x" onmousemove="('comment',' On the lower part of the deed which is left unfolded. ');">⁷</span> whatever he wished and induce additional witnesses to sign on the outside;<span class="x" onmousemove="('comment',' On the back of the additional written matter. ');">⁸</span>

וליחוש דלמא מתרמיא ריעותיה בשיטה אחרונה וגייז ליה לשיטה אחרונה וגייז ליה לראובן בהדיה ומתכשר בבן יעקב עד דתנן בן איש פלוני עד כשר

and might say, 'I did it<span class="x" onmousemove="('comment',' Added extra witnesses over and above the prescribed number of three. ');">⁹</span> in order to increase the number of witnesses'?<span class="x" onmousemove="('comment',' To give the matter greater publicity. ');">¹⁰</span>

דכתיב ראובן בן בחד דרא ויעקב עד עלוויה

— He<span class="x" onmousemove="('comment',' R. Hisda. ');">¹¹</span> replied to him:<span class="x" onmousemove="('comment',' Rami b. Hama. ');">¹²</span>

וליחוש דלמא גייז ליה לראובן בן ומתכשר ביעקב עד דתנן איש פלוני עד כשר

Do you think [that] witnesses<span class="x" onmousemove="('comment',' According to R. Jeremiah. ');">¹³</span> sign in the [same] order [as the lines of the deed],<span class="x" onmousemove="('comment',' I.e., in horizontal lines on the reverse of the deed, corresponding to the lines on the obverse, the first signature corresponding to the first line of the deed, the second to the second, and so on. If that were the case, spurious matter could certainly be added. ');">¹⁴</span>

דלא כתיב עד

they sign [vertically] from bottom to top?<span class="x" onmousemove="('comment',' They begin their signatures at the bottom of the reverse, on the back of the last line of the obverse, and proceed vertically upwards, witness after witness, towards the top line. Since the first signature commences at the foot of the deed, any matter below it (not having a signature on the reverse) would be easily detected as spurious. ');">¹⁵</span> But is [there no reason] to apprehend [that some] unfavourable condition might occur in the last line [of the deed] and he would cut off that last line, and [though] with it he would [also] cut off [the name of the witness] 'Reuben',<span class="x" onmousemove="('comment',' Written on its back. ');">¹⁶</span>

ואיבעית אימא לעולם דכתב עד דידעינן בה דהא חתימות ידא

[the deed] would [yet] remain valid through [the remaining part of the signature], 'son of Jacob witness';<span class="x" onmousemove="('comment',' The proper form of a signature was, 'X son of Y, witness'. The algebraic symbols are represented in the Talmud by the Biblical characters, Jacob and his son Reuben. ');">¹⁷</span> as we learnt: [The signature]. 'son of X, witness', is valid?<span class="x" onmousemove="('comment',' Git. 87b. ');">¹⁸</span> — [The witness] writes, 'Reuben son of', across one line,<span class="x" onmousemove="('comment',' So that by cutting off the last horizontal line of in the deed, 'Reuben son of' which is written vertically on the other side is cut off with it. ');">¹⁹</span> and, 'Jacob. witness', above it.<span class="x" onmousemove="('comment',' Above the last line and across the back of the second line (from the bottom) of the text; and this, i.e., the name only of the father of the witness, would remain on the deed were the last line to be cut off. [(V. fig. 1, cf. Fischer loc. cit.)]. According to the description of the Yad Ramah, the signatures appear thus (v. fig. 2). ');">²⁰</span> Is [there no reason, however,] to apprehend that [though] he might cut off, 'Reuben son of', [the deed] would [yet] remain valid through [the remaining portion of the signatures]. 'Jacob, witness';<span class="x" onmousemove="('comment',' The court mistaking the name of the father for the name of a witness, regarding 'Jacob' as the name of the witness. ');">²¹</span> as we learnt: [a signature], 'X, witness' is valid?<span class="x" onmousemove="('comment',' Git. l.c. ');">²²</span> — [The word], 'witness' is not written.<span class="x" onmousemove="('comment',' In such a case, the name of a witness without the name of his father is invalid. Hence, should one line of the deed be cut off leaving the name of the witness's father only on the remaining portion of the deed, the signature would be invalid. ');">²³</span> And if you wish it may be said [that a witness], in fact, does write [after his signature], 'witness', [but this is a case] where it is known that the signature