Study Pesachim folio 9A with parallel Hebrew-English text, traditional commentary, and modern study tools. Free access to Babylonian Talmud online.
Text Excerpt
מתני׳ אין חוששין שמא גיררה חולדה מבית לבית וממקום למקום, דאם כן מחצר לחצר ומעיר לעיר — אין לדבר סוף.
Mishnah: After conducting the search, one need not be concerned that perhaps a marten dragged leaven from house to house, or from place to place, placing leaven in a house that was already searched. As if so, one need also be concerned that perhaps leaven might have been dragged from courtyard to courtyard and from city to city. In that case, there is no end to the matter, and it would be impossible to rely on any search for leaven.
Talmud: The Talmud infers from the Mishnah: The reason that one need not search again is that we did not see the marten drag the leaven from the house; however, if we saw the marten drag leaven from the house, we are indeed concerned that it dragged the leaven into the second house, and it therefore requires searching for leaven.
ואמאי? נימא אכלתיה! מי לא תנן: מדורות הגוים טמאים. וכמה ישהה במדור ויהא המדור צריך בדיקה — ארבעים יום.
The Talmud raises a difficulty: But why is this so? Let us say that the marten ate the bread it took. Didn’t we learn in a Mishnah: The residences of non-Jews are ritually impure, as their wives may have miscarried, and due to the fact that non-Jews would bury their stillborn babies in their houses, all their residences are deemed ritually impure due to the possibility of impurity imparted by a corpse. And how long must a non-Jew have stayed in a residence for the residence to require searching? He must have lived there for 40 days. The reason is that until 40 days after conception the miscarried fetus is not classified as a stillborn, as it is not sufficiently developed before that stage.