with regard to the combination of two pieces vis-à-vis ritual impurity during Passover, when it depends upon their volume. However, during the rest of the year there is a distinction based upon whether the owner is particular about it or not.

The Gemara explains: What are the circumstances of the mishna’s case? It is a case where there is less than an egg-bulk of ritually impure food, and it touched this dough in the bowl, and then it came into contact with ritually pure food. During Passover, when the prohibition that applies to the dough causes it to be considered significant although it is a very small quantity, it combines with the first piece of food. Together they are the size of an egg-bulk, which is able to transmit the ritual impurity of foods. However, during the rest of the year, when there is no prohibition that imparts this significance to the dough, the matter is dependent on the owner’s particularity; if he is particular about it, i.e., he does not want the dough to be there, it is considered food rather than part of the bowl, and it combines with the other piece of food. However, if one prefers its continued presence in its current location, it is considered like part of the kneading bowl itself, rather than food.

Rava strongly objects to this: Was the language taught in the mishna: Combines? Didn’t the mishna teach that it interposes? Abaye’s explanation does not account for this term. Rather, Rava said that the mishna should be understood as saying: And so too with regard to purifying the kneading bowl via immersion.

The Gemara explains: What are the circumstances of the mishna’s case? It is a case where the kneading bowl became ritually impure, and one wishes to immerse it. During Passover, when the prohibition of an olive-bulk of leaven causes it to be considered significant, it interposes between the water and the kneading bowl, and the immersion is ineffective. However, during the rest of the year, the matter depends upon whether or not the owner is particular about it. If he is particular about the dough and wishes to remove it, it interposes between the water and the bowl. However, if the owner desires it to be present, it is considered like part of the kneading bowl itself, and it does not interpose between the water and the bowl.

Rav Pappa strongly objects to this: Was the language taught in the mishna: And similarly with regard to ritual purity? Didn’t the mishna teach: And similarly with regard to ritual impurity? Rather, Rav Pappa said the mishna should be understood as saying: And similarly with regard to the transfer of ritual impurity to the kneading bowl via this dough.

The Gemara explains: What are the circumstances of the mishna’s case? It is a case where the carcass of a creeping animal touched this dough. During Passover, when its prohibition causes the dough to be considered significant, it interposes between the bowl and the creeping animal, and ritual impurity does not descend to the kneading bowl, i.e., the kneading bowl does not become impure. During the rest of the year, when it depends upon whether one is particular about the presence of the dough, if he is particular about it, it interposes between the bowl and the creeping animal and prevents the bowl from becoming impure. However, if he desires it to be present, it is considered like it is part of the kneading bowl itself. Therefore, the entire bowl becomes ritually impure when the carcass of the creeping animal touches the dough.

MISHNA: Deaf dough is dough for which it is difficult to determine if it has been leavened. It is comparable to a deaf-mute, who cannot communicate. If there is dough similar to it in that water was added to both at the same time, which became leavened, the deaf dough is prohibited. Although it has not shown external signs of becoming leavened, it can be presumed that the deaf dough has also become leavened.

GEMARA: The Gemara seeks to clarify the ruling of the mishna: If there is no dough similar to it, what is the halakha? Rabbi Abbahu said that Rabbi Shimon ben Lakish said: According to the Sages, leavening occurs in the time it takes a person to walk the distance from Migdal Nunaya to Tiberias, which is a mil, two thousand cubits.

The Gemara asks about this formulation: Why is it necessary to mention the distance between these two places? Let us say that leavening begins after the time it takes a person to walk a mil. The Gemara answers: This statement incidentally teaches us that the length of a mil is the distance from Migdal Nunaya to Tiberias.

Rabbi Abbahu said that Rabbi Shimon ben Lakish said: With regard to a kneader, i.e., one who kneads dough for others and should maintain the ritual purity of the dough; and similarly, with regard to washing one’s hands for prayer (Arukh), and with regard to washing hands before eating, one must search either for a ritual bath to immerse the vessel he is using to knead the dough, or for water to purify his hands, provided that water is accessible within the time it takes to walk four mil, eight thousand cubits.

Rav Naḥman bar Yitzḥak said: Ayvu said this halakha, and he said it about four cases, as opposed to the three cases mentioned previously. And one of them pertained to the tanning of hides, which lasts for the time that it takes a person to walk four mil. As we learned in a mishna: And all types of thin, soft hides, which have the status of flesh with regard to ritual impurity because their texture is similar to flesh, that were tanned in order to be made into leather, or that one trod upon for as long as necessary for the leatherworking process, are ritually pure. They are considered to be leather and are no longer considered like the flesh of the animal, except for the skin of a human corpse, which always remains ritually impure. The Gemara asks: How much time must one tread upon a hide for the leatherworking process? Rabbi Ayvu said that Rabbi Yannai said: It is the amount of time it takes to walk four mil.

Rabbi Yosei, son of Rabbi Ḥanina, said: They taught that one must search for water to wash one’s hands before eating or prayer for the amount of time it takes to walk four mil only when the water is before him, in the direction that he is traveling. However, when it is behind him, he need not return even a mil. Rav Aḥa said: From this statement one may infer that he need not return a mil, but he must return less than one mil in order to obtain water.

MISHNA: How does one separate ḥalla in ritual impurity during the Festival day of Passover? Ordinarily, one may separate ritually pure ḥalla from dough and give it to a priest immediately so that he may eat it. Ritually impure ḥalla is unfit for a priest and must be burned, yet it is prohibited to bake or burn anything that is not fit to be eaten during the Festival day. However, it is also prohibited to wait and burn it after the Festival day, since it will become leavened in the meantime.

Rabbi Eliezer says: A woman should not designate it as ḥalla prior to baking; rather, she should refrain from doing so until it is baked. In other words, she should wait until she has baked all of the dough, and there is no risk of it becoming leavened. Only then should she separate ḥalla from it. The portion of ḥalla may then be kept until after the Festival day, when it may be burned. Ben Beteira says: She should separate the ḥalla before it is baked, and place the dough in cold water so that it will not become leavened. Rabbi Yehoshua said: