[19a - 41 lines; 19b - 51 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.
 Gemara 19a [line 21]:
The words "d'Rebbi Yishmael Nami Lo Ba'i Yedi'ah" דרבי ישמעאל נמי לא בעי ידיעה
should be "d'Rebbi Yishmael Lo Ba'i Nami Yedi'ah" דרבי ישמעאל לא בעי נמי ידיעה (or the word "Nami" should be removed altogether, as is the Girsa in Shevuos 14b — Rashash)
 Rashi 19a DH Shachach she'Halach b'Rosho ד"ה שכח שהלך ברשע:
The words "Ika Tum'ah Yedi'ah Vada'is" איכא טומאה ידיעה ודאית
should be "Ika Tum'ah v'Yedi'ah Vada'is" איכא טומאה וידיעה ודאית
 Rashi DH v'Rebbi Shimon Ben Yehudah ד"ה ורבי שמעון בן יהודה:
The words "d'Tum'as Yedi'ah Vada'is Hi" דטומאת ידיעה ודאית היא
should be "d'Tum'ah Vada'is Hi" דטומאה ודאית היא
 Rashi DH she'Hu Chayav ד"ה שהוא חייב:
The words "Eizo Melachah" איזו מלאכה
should be "v'Eizo Melachah" ואיזו מלאכה
 Rashi DH Miba'i Lei ד"ה מיבעי ליה:
The words "v'Iy Kashya Im Ken ..." ואי קשיא אם כן are the beginning of a new Dibur ha'Maschil, and belong on 19b, Rashi DH Meleches Machsheves Asrah Torah "v'Iy Kashya Im Ken ..." מלאכת מחשבת אסרה תורה ואי קשיא אם כן (see Bach to Daf 19b #1 and the marginal note of the Rashak there)
 Rashi 19b DH Mis'asek b'Arayos ד"ה מתעסק בעריות:
(a) The words "Kegon she'Niskaven Lavo Al Ishto Nidah v'Savur Tehorah Hi" כגון שנתכוון לבא על אשתו נדה וסבור טהורה היא are difficult to understand, since that is a case of Shogeg and not Mis'asek, as Rashi wrote above and at the end of the previous Dibur, and as the Shitah Mekubetzes #19 and the Rashash ask.
(b) Perhaps these words belong at the end of the previous Dibur, which does refer to Shogeg rather than Mis'asek. (The Rashash and Olas Shlomo emended Rashi in other ways.)
 Rashi DH ul'Rebbi Yosi ד"ה ולרבי יוסי:
(a) Should be corrected as suggested by Shitah Mekubetzes #20
(b) The words "Amai Ka'amar" אמאי קאמר
should be "v'Amai Ka'amar" ואמאי קאמר
 Rashi DH Chata v'Eino Yode'a b'Mai Chata ד"ה חטא ואינו יודע במאי חטא:
The words "O Safek Chata O Safek Lo Chata" או ספק חטא או ספק לא חטא are the beginning of a new Dibur
 Rashi DH Afilu Rebbi Yehoshua Mechayev ד"ה אפילו רבי יהושע מחייב:
(a) These words are the continuation of the previous Dibur and not the beginning of a new one
(b) These words should read "v'Hacha Afilu Rebbi Yehoshua Mechayev" והכא אפילו רבי יהושע מחייב
1)[line 23]מגמרא אית ליהMI'GEMARA IS LEI- his ruling was based on a tradition (as opposed to a ruling based on a specific verse)
2)[line 37]אם כן, למה נאמר "אשר חטא בה"IM KEN, LAMAH NE'EMAR "ASHER CHATA BAH"- (The words "Im Ken" are like "v'Chi Teima":) if you will ask, when will the verse "Asher Chata Bah" exempt one from a Chatas, the answer is when the person intended to perform a permitted act but unknowingly sinned (RASHI; other Rishonim explain these words in a similar fashion)
3a)[line 37]פרט למתעסקPRAT L'MIS'ASEK- this excludes the case when a person intended to do (lit. was occupying himself with) an action in a situation where it is permitted, and accidentally performed the same action in a situation where it is forbidden. For example, if a person planned to cut a melon that was detached and actually cut one that was still attached to the ground. (RASHI, see next entry and Insights)
A person must bring a Korban Chatas for desecrating Shabbos only when he does a Melachah b'Shogeg, that is, mistakenly not knowing that the day is Shabbos or not knowing that the action that he did is a Melachah that is prohibited on Shabbos. However, a person who is Mis'asek, i.e. who does a completely different action from that which he intended to do, incurs no punishment whatsoever. (See Shabbos Chart #14, where the differences between Shogeg and Mis'asek are explained.)
4)[line 2]המתעסק בחלבים ועריותHA'MIS'ASEK B'CHALAVIM V'ARAYOS- the exemption of Mis'asek (see previous entry) does not apply when the prohibition involved is forbidden foods (the example given is Chelev) or Arayos, since the person has a direct physical pleasure from it
5)[line 3]אלא מתעסק בשבת פטור(V'IY) [ELA] MIS'ASEK B'SHABBOS PATUR- Rashi's Girsa is "Ela," as the Bach #1 and Shitah Mekubetzes #2 suggest. This is the Gemara's answer: When is Mis'asek Patur? -In Hilchos Shabbos, as Rav Nachman says... (see Insights)
6)[line 4]מלאכת מחשבת אסרה תורהMELECHES MACHSHEVES ASRAH TORAH
The Torah only forbids actions performed on Shabbos with intent, and not actions that were performed accidentally.
7)[line 5]לרבא משכחת להL'RAVA MISHKACHAS LAH- see Insights
8)[line 29]"[ואם נפש] כי תחטא [ועשתה אחת מכל מצות ה' אשר לא תעשינה] ולא ידע [ואשם ונשא עונו]""[V'IM NEFESH] KI SECHETA [V'ASESAH ACHAS MI'KOL MITZVOS HASH-M ASHER LO SE'ASENAH;] V'LO YADA [V'ASHEM, V'NASA AVONO.]"- "[And if a person] sins, [and commits any of [the things that are forbidden to be done by] the commandments of HaSh-m;] though he knew it not, [yet he is guilty, and shall bear his iniquity.]" (Vayikra 5:17)
9)[line 42]טעה בדבר מצוה ולא עשה מצוה פטורTA'AH BI'DVAR MITZVAH V'LO ASA MITZVAH, PATUR
(a)A person offers a Korban Chatas if he transgresses a prohibition b'Shogeg (unintentionally) for which the Kares punishment applies for intentional transgression. A person offers a Korban Asham for Me'ilah b'Shogeg, unintentionally benefiting from Kodshim.
(b)If a person does an Aveirah that makes him liable to bring a Korban Chatas or Asham, but he thought that he was actually performing a Mitzvah of the Torah through his action, the Tana'im argue as to whether he is liable to bring a Korban or not.
(c)Even if To'eh b'Devar Mitzvah is exempt, there are various opinions among the Tana'im and Amora'im with regard to exactly when this exemption applies and when it does not:
1.Some say a person is exempt only when he eventually performs a Mitzvah through his actions. If he does not perform a Mitzvah, he is not exempt. This is the subject of an argument between the Tana Kama and Rebbi Meir in Pesachim 72a.
2.Others say that the exemption of To'eh b'Devar Mitzvah only applies when the person is in a rush because his time is limited ("Zemano Bahul"). If he has the option of doing the Mitzvah on the next day, he is liable to bring a Korban Chatas. (This is the reasoning of the Gemara Pesachim 72b, as opposed to the opinion of Rebbi Yochanan there.)
3.Still others rule that we only exempt ha'To'eh (one who makes a mistake) b'Devar Mitzvah, and not someone who was Shogeg b'Devar Mitzvah (where he transgresses the Isur accidentally due to a lack of care) — RASHI to Pesachim 73b DH Im Yesh Shehus, and to Sukah 42a DH mi'Lishkah. (These are just some of the numerous details of this Halachah. More details are discussed in Pesachim 72b.)
(d)Our Gemara brings the Mishnah that describes a case of a Mohel who was to perform Bris Milah on two boys, one on Shabbos and one on the following morning. He performed Bris Milah on Shabbos on the wrong baby by mistake. He is a To'eh b'Devar Mitzvah and he is exempt from a Korban.
10)[line 48]שיננא!SHINENA!- well-learned (sharp) person!
11)[line 49]שבוק מתני' ותא בתראיSHEVOK MASNISIN V'SA BASRAI- (lit. leave our Mishnah, and come after me) explain the case the way I do