1. A בריה of any size qualifies as a יד

On the previous Daf, Rav said that a יד is effective only for a כזית or more of food, and a שומר requires at least כפול. Rebbe Yochanan said that a יד is effective for less than a כזית, and a שומר for less than a כפול. On this Daf, the Gemara proves that at least one of these questions is a machlokes Tannaim. Rav is further challenged from a Baraisa taught in Rebbe Yishmael’s yeshivah, which darshened: על כל זרע זרוע אשר יזרע – upon any seed of a seed-plant which is sown, implying כדרך שבני אדם מוציאין [לזריעה] – seeds which are the way people take them out for planting. Thus, חטה בקליפתה – wheat in its husk, or barley or lentils in their husks, can contract tumah through their husks, because the husk is a שומר. Since a lentil is smaller than a כפול, this seemingly proves that a שומר does not require a כפול to be effective!? The Gemara answers: בריה שאני – an entire creation, such as a whole lentil, is different, and its שומר is effective even for less than a כפול.

1. Combining two שומרין

Rav Oshaya asked: שני שומרין מהו שיצטרפו – what is the halachah regarding two שומרין combining with the foods they protect to comprise the minimum shiur for tumah? This cannot refer to one שומר on top of another שומר, because a Mishnah teaches that the outer peel of an onion is not considered a שומר, since the peel underneath it is a שומר. Rather, Rav Oshaya’s question was about שומר אוכל שחלקו – the שומר of a food which one divided into two, so each שומר only protects part of the food, and both שומרין together with the food amount to a כביצה. Do we say כיון דהאי לא מגין אהאי – since this [part of the שומר] does not protect this [part of the food], and the other part of the שומר does not protect the other part of the food, the שומרין do not combine for tumah? Or do we say כיון דהאי מגין אדידיה והאי מגין אדידיה – since this [שומר segment] protects its [food segment] and that [שומר segment] protects that [food segment], they do combine with food for the minimum shiur for tumah? The proofs proposed to resolve this question are deflected.

1. Machlokes if a נימא (a strand of hair) qualifies as a יד

A bone with a כזית of meat on one end is metamei the contents of a house if the other end entered the house, based on the principle of יד. Reish Lakish says this only applies to a bone, אבל נימא לא הויא יד – but a strand of hair is not an effective יד, since it would tear if he would try to lift the meat with it. Rebbe Yochanan says that even a נימא is considered a יד. Reish Lakish is challenged from a Mishnah teaching that touching a hair growing opposite meat is metamei. In the second answer, the Gemara explains that the Mishnah refers to נימא שבין הנימין – a strand of hair among many strands, which together are strong enough to lift the meat. In another version, all agree that a single strand of hair does not qualify as a יד, and Rebbe Yochanan and Reish Lakish argue whether a bunch of hairs qualifies as a יד. In a third version, Rebbe Yochanan and Reish Lakish argue whether a נימא qualifies as a שומר.