Episode Details

The Gemara continues analyzing Rava's attempt to prove that "touch" (maga) can include tent-impurity (ohel) based on Rabbi Yosi's ruling regarding bed frames and window bars. Abaye rejects this proof, explaining that the case involves a space under a handbreadth (tefach), and due to a challenge raised against his explanation, Abaye is forced to explain that Rabbi Yosi holds concealed impurity does not break through (tumei tmunah eina boka'at). He proves his stance on concealed impurity from a Mishna discussing a cabinet (migdal) and Rabbi Yosi's commentary on it. A challenge is raised against Abaye from another case where Rabbi Yosi appears to hold that concealed impurity does break through and ascend (a dead dog that swallowed corpse flesh and is lying on a threshold). Rava resolves this by explaining that Rabbi Yosi does not rely on concealed impurity breaking out, but rather his dispute with Rabbi Meir regarding the dog is based on other considerations - whether the cavity of the dog contains a handbreadth of space and whether the threshold is considered part of the house.

The Gemara returns to clarify the identity of Rabbi Yosi's disputant, who holds that tent-impurity is not included in the term "touch." The Gemara identifies him as Rabbi Shimon, who disagrees with Rabbi Yosi in a braita by stating that there are three items that impart corpse-impurity through only two of the three standard modes (touch, carrying, and tent): a ladleful of dust of a human carcass (melo tarvad rakav) imparts impurity through carrying and tent, but not touch; a barley-grain-sized bone (etzem k'seorah) imparts impurity through touch and carrying, but not tent; and a tombstone lid and supporting frame (golel v'dofek) impart impurity through touch and tent, but not carrying. His ruling regarding dust demonstrates that he does not categorize tent-impurity under touch.

Regarding a carcass marrow-bone (kulit), the braita cites a scriptural source establishing that a sealed marrow-bone does not impart impurity, whereas a perforated one does. Rav Oshaya inquires whether a sealed marrow-bone that one intends to perforate is considered "lacking an action" (mechusar ma'aseh) because it requires perforation, or is it already considered perforated and can pass on impurity. He concludes that one's intent to perforate would make the bone susceptible to impurity.

The Mishna rules that a formed embryo egg of a creeping creature (sheretz) is pure unless perforated. Regarding a mouse that is half flesh and half earth, touching the flesh imparts impurity - and according to Rabbi Yehuda, touching earth directly opposite the flesh also imparts impurity. Analyzing the Mishna, the Gemara brings a braita deriving that a sheretz egg requires embryo formation (rikem) and a perforation as thin as a hairbreadth (k'chut ha-se'arah) to transmit impurity. Rabbi Yehoshua ben Levi clarifies that the half-earth mouse transmits impurity only if it developed flesh across its whole body. The braita discusses whether a sea-mouse is subject to the same laws of impurity as a land-mouse.