Question: Rebbi Yishmael was referring to a case where he did not gather it, and Rebbi Yehudah requires gathering, as stated by Rav Huna!

Answer #1: The argument between Rebbi Yishmael and Rebbi Akiva is when an animal ripped off the skin. This is why Rebbi Yishmael does not require the meat to be gathered. However, if the meat was taken off due to the skinning, if it is not nullified to the skin according to Rebbi Yishmael it requires gathering.

Answer #2: Additionally, it is possible to explain that Rebbi Yishmael is also referring to gathering. This is not difficult to say, as Rebbi Yehudah's words are also explained in this fashion.

Implied Question: The Gemara earlier (121a) says that according to the opinion that says it was partially bit off by an animal and partially skinned, this opinion understands that the argument regarding a case where it was totally due to being skinned is an argument between Rebbi Yehudah and the Rabbanan. According to Rebbi Yehudah it is not nullified. Even so, one cannot ask according to this opinion, "Who does Rebbi Yehudah hold like" as we ask here, "If you say that according to Rebbi Yishmael it is nullified etc." (Why not?)

Answer: This is because we can say Rebbi Yehudah holds that together there is a Kzayis. However, the question here is valid according to Rav Huna, as explained by Rashi. (See Maharam at length regarding the explanation and possible mistake in the text of this Tosfos.)

Question: Perhaps when Rav Huna says that two half Kzaysim on the skin are nullified by the skin, he is referring to a case where they were not gathered together? However, if he gathered them together, he admits that they are not nullified.

Answer: This is obvious! Rav Huna does not have to say that the skin nullifies them (if they are not gathered together).

Explanation: This is as the Gemara in Nidah (55a) explains that skin is not the same as human bone, as skin regenerates.

Implied Question: The Gemara gives the reason as one possibly making the skin of his father and mother into carpets even though every dead person is forbidden from benefit, and one is not allowed to make carpets out of anyone's skin. (Why, then, did the Gemara specifically state the reason regarding the skin of his father and mother?)

Answer: The Rabbanan would not have decreed that skin is impure due to this suspicion if it were not for the fact that a person would come to do this to the skin of his father and mother, which would be a more stringent sin.

Answer (cont.): One does not have to answer that it said the skin of his father and mother because these are the skins that he would normally have access to in order to make them into carpets.

Explanation: This opinion deems skin as something that does not regenerate, as it turns into a scab on the flesh as stated in Nidah (ibid.).

Question: This is difficult. The Gemara could still ask that it is possible that Ula says he must be one year old whether or not he nurses, and Rebbi Yochanan said to him that he has to be nursing, whether he is a year old or not!

Answer #1: It is not logical that there is such a vast difference between their opinions. This is why the Gemara does not entertain this possibility.

Answer #2: Rebbi Yaakov from Korvil answered that the Gemara understands that even if the animal is less than a year old but does not nurse, its skin is tougher than an animal that does not nurse and is over a year old. (This gives no room for the understanding suggested in the question.)

Answer #2 (cont.): Accordingly, since Rebbi Yochanan said, "as long as he nurses" it is obvious that Ula holds that he must be one year and nursing. If he would be saying that he must be less than a year whether he nurses or not, certainly if he would over a year and nursing his skin would be considered soft! If so, what would Rebbi Yochanan be adding by saying "as long as he nurses?" Ula admits that this is certainly true!

Explanation: He was asking regarding an incident that took place. He clearly knew the Mishnah, as indicated by his question on Rebbi Yochanan later.

Question: This is difficult, as the Gemara earlier (112b) states that "that are impure" forbids their brine and gravy. However, there as well "according to its type" separated the Pasuk, as the words being referred to are all in the same Pasuk as explained by Rashi!

Answer: In our case, all of those who are excluded have skin that is felt (as a thick separate entity from its skin). It is therefore logical to establish that this refers to those who are named after the word "according to its type."

Implied Question: This is despite the fact that a Tinshames is listed amongst these Sheratzim and its skin is thick, yet we still include it in the previous list. (The Tosfos ha'Rosh suggests that perhaps its skin is not thick enough to be excluded.)

Answer (cont.): However, the brine and gravy mentioned earlier (12b) logically apply to all of them.

Question: This is slightly difficult, as since there is a new topic, why is the word "these" necessary?

Explanation #1: Rashi explains that Rebbi Yehudah does not hold of the derivation of "that are impure."

Observation: According to his explanation, the Tana of the Beraisa is neither Rebbi Yehudah nor the one who argues on him.

Implied Question: Rashi did not have to say that Rav is a Tana and therefore can argue, as the Tana of the Beraisa holds like him!

Explanation #2: It is possible to explain that everyone holds of the derivation from "that are impure." Logic dictates that the inclusion is referring to those who skin does not feel separate (i.e. it is very thin) from its flesh, and the exclusion is referring to those whose skin is separate. This would not require "according to its type" to separate the two categories. However, according to Rav who does say that "according to its type" separates the two categories, it must be that he argues on these opinions and considers Tinshames as one of those whose skin is like its flesh.

Explanation: The flesh that was in the ear was nullified.

Explanation #1: Rashi explains that the Gemara is asking that the Mishnah should suffice with putting it down in front of the one who steps on it without him actually stepping on it.

Question: This is difficult, as if this is the case, what is the answer that the Beraisa is referring to a case where he treated it as a skin but did not yet walk on it? The question remains that the Mishnah should say he put it before the one who steps on it without walking on it!

Explanation #2: It therefore must be that the explanation is that if he went with it, it is considered pure. If he treated it as a skin, it is not. This is apparent from the fact that the Mishnah did not say that he treated it as a skin. One might have thought that treating it as a skin is worse than walking on it. The Gemara answers that treating it as a skin is enough even if he did not walk on it, meaning that each is sufficient and there is no difference between the two. (This is why it is not difficult that the Mishnah did not mention treating it as a skin, as it did mention walking on it.)

Explanation #1: Rashi explains that this is refers to someone who is supposed to mix his friend's dough while pure. He must walk four Mil in order to purify his vessels.

Implied Question: According to this explanation, Rebbi Yosi bar Chanina's comment (123a) regarding whether it is on his way or behind him cannot be discussing this case, as it is uncommon for a person to hire someone who is traveling to mix his dough. (Since the Gemara implies Rebbi Yosi is referring to this case as well, Rashi's explanation seems difficult.)

Explanation #2: It appears that the Aruch's explanation is correct. He explains that if a person knows that there is someone who can make him his dough four Mil down the road, he should wait until he gets to that person to make his dough. Rebbi Yosi is discussing a person who is traveling. (The Maharam explains that "make him his dough" means that the person can buy bread from someone who does not make it while his vessels are pure, or four Mil later from someone who sells bread that he makes while pure.)

Explanation #2 (cont.): The Aruch continues that when the Gemara says, "for Tefilah" it refers to washing one's hands before Davening.

Question: This seems difficult. What is the case? If the case is where it is time for him to Daven, Abaye in Berachos (15a) cursed someone who went to find water when it was already time to Daven. This is because the Pasuk says, "I will wash with cleanliness my hands" implying anything that cleanses is sufficient (and water is not required). If it was not yet time to Daven, why does he only have to walk four Mil? He should walk even further!

Explanation #1: It therefore appears that Rashi is correct, that this is referring to him having to travel to Daven with a Minyan.

Question #1: It is difficult to understand why Rebbi Avahu did not include our Mishnah's case of working the skin on this list.

Question #2: Additionally, according to the one who counts this on his list, why doesn't he include the case regarding thirty Ris mentioned in Bava Basra (23a), as the measurement of a Mil is seven and a half Ris?

Explanation #3: Rabeinu Chananel explains that "Tefilah" here means to immerse in order that his Tefilah should be said while pure.

Implied Question: This is despite the fact that we hold like Rebbi Yehudah ben Beseirah regarding learning (that one does not have to be pure to learn Torah). (Why, then, should he have to immerse?)

Answer #1: This is only regarding learning Torah and reciting Kriyas Shema, not regarding Davening.

Answer #2: Alternatively, it is possible that he does not hold like Rebbi Yehudah ben Beseirah (who would permit Davening without immersing).

Answer: According to Rabeinu Chananel, it is understandable why working skins is not included, as only these three items were included by Rebbi Avahu since they are regarding purity. The opinion that added working the skins did so because it is also in a sense regarding a matter of purity, as it causes the skin to become pure and be unable to become impure. This is why we find this case was added, but nobody added the case of thirty Ris (which has to do with one deals with pigeons).