[50a - 53 lines; 50b - 44 lines]
We recommend using the textual changes suggested by the Bach and the marginal notes of the Vilna Shas. This section is devoted to any other important corrections that Acharonim have pointed out in the Gemara, Rashi and Tosfos.
 Tosfos 50a DH Aval, at the end: אבל
The words "v'Rashi Lo Piresh Ken" ורש"י לא פירש כן
should be "v'Ri (i.e. Rabeinu Yehudah) Lo Piresh Ken" ור"י לא פירש כן
This seems to be the correct Girsa, but see Divrei Nechemyah (printed in our Gemaras after Maseches Berachos).
 Hagahos ha'Gra [to Rashi DH mishe'Nasan] 50b #2, 3
The Vilna Ga'on intends to argue with Rashi rather than to explain Rashi (as he does many times in Hagahos ha'Gra). That is why he erased these words.
1)[line 7]הנקדניןHA'NAKDANIN- (a) exacting, meticulous people (RASHI); (b) boorish people (TOSFOS RI HE'CHASID and TOSFOS HA'ROSH, citing the ARUCH)
2)[line 22]על המזון שאכלנו הרי זה בורAL HA'MAZON SHE'ACHALNU, HAREI ZEH BUR- (a) since he did not say "mi'Shelo," and it is not clear that he is thanking HaSh-m (RASHI); (b) since it seems like he is praising his host, because he only mentioned food. Were he praising HaSh-m, he would have had much more for which to be thankful (TOSFOS DH Al)
3)[line 37]אוושו כולי עלמאAVSHEI KULEI ALMA- everyone is making noise
4)[line 39]אינון נפקין בזמון דידיהINUN NAFKIN B'ZIMUN DIDEI- they have fulfilled their obligation of Zimun, even though the third person already said Birkas ha'Mazon before he answered their Zimun
5)[line 39]אין זמון למפרעEIN ZIMUN L'MAFRE'A
A person cannot fulfill his obligation of Zimun after he recites Birkas ha'Mazon.
6)[line 40]קם קרא בספראKAM KARA B'SIFRA- he got up and read in the Torah
7)[line 42]פתיא אוכמאPASYA UCHMA- black pot, i.e. you are also well-versed in the Torah, as much as a pot is blackened from use (RASHI to Avodah Zarah 16b)
8)[line 1]אזמון עלייהוAZMUN ALAIHU- made a Zimun with them
9)[line 6]טהורהTEHORAH (KELIM: TUM'ASAN V'TAHARASAN)
(a)The term "Klei Shetef" refers to all utensils that can be immersed in a Mikvah to make them Tahor. This includes metal and wooden utensils, clothing, leather goods and sacks. They are called Klei Shetef based on the words of the verses, "and if it is cooked in a copper utensil, it must be emptied and immersed ("v'Shutaf") in a Mikvah" (Vayikra 6:21) and "If it is a wooden utensil, it must be immersed ("Yishatef") in a Mikvah" (Vayikra 15:12).
(b)A utensil is considered ready to receive Tum'ah only after it is completely finished. If the artisan even decided that the utensil needs no more work, it is considered complete and may become Tamei. If the artisan afterwards decides to do more work on the utensil, it remains Tamei until an action is performed on the utensil that makes his intention clear (Kidushin 59a-b).
(c)The action that must be performed to change the status of a utensil must be an action that renders the utensil unfit for its original purpose. For example, if a tanner decided to use a hide as a rug, it may become Tamei from that moment on. If he then changes his mind and decides to make shoes out of it, it remains in its current status until he begins to cut the hide for shoes.
(d)If a utensil breaks and as a result is unusable, it becomes Tahor. Metal and glass utensils that become Teme'im may be immersed in a Mikvah to return them to a state of Taharah. An earthenware utensil that becomes Tamei has only the option of being broken (see Background to Nidah 60:10). In our Sugya, a bed that was Tamei was cut into two pieces. As a result, it becomes Tehorah and remains as such, even after it is put back together. TOSFOS DH she'Chilkuhah (1st answer) specifies that if a non-craftsman can put it back together, it remains Tamei.
(e)For a further discussion of the principles of Tum'os and Taharos, see Background to Nazir 54:13.
10)[line 20]כוס של ברכהKOS SHEL BERACHAH- the cup of wine used for Birkas ha'Mazon
11)[line 23]קורייטיKURAITEI- (O.F. poison) beverage
12)[line 28]פתקPASAK- he threw
13)[line 29]דסתנאDISTENA- (O.F. amenestraison) a portion [of cooked meat]
14)[line 36]קליותKELAYOS- parched grains
15)[line 38]גלוסקאותGELUSKA'OS- loaves of bread or cakes
16a)[line 41]בולעןBOL'AN- he swallows them
b)[line 41]פולטןPOLTAN- he spits them out
c)[line 42]מסלקןMESALKAN- he moves them to one side of his mouth