Shiur Supplement #16 Daf 9b
A. Rashi s.v. Leida im zakhar im nekeiva - The kohein peered into the pit in order to ascertain the sex of the miscarried fetus. This was of importance in order to ascertain the length of time the mother would be impure: If the fetus was male, she would count seven days during which time we would considered like a nidda (menstruant woman). Thereafter, she would immerse in a mikve and count 33 days during which time she would be considered tehora, even if she experienced an emmission of blood. Once this time period had elapsed, she would bring two korbanot (chatat and asham) and, thereby, be permitted to partake of sacrifices once more. If the fetus was female, however, she would count a period of 14 days, followed by one of 66 days. [See Vayikra 12:1-8]
Note: Today, however, if a woman experiences an emmission of blood during the SECOND set of days (33 or 66 depending on the sex of the fetus) she is considered a nida. The same laws apply to a woman who gives birth to a live child.
B. Mipnei she-chulda u-bardelas metzuyin sham [line 3] The fetus has the ability to defile a person if if stands directly above it, thus there is a chance that the kohen became impure by peering into the pit. However, the Rabbis declared the kohen to be tahor (ritually pure). Since weasel and martens roam the area, we rely on the fact that the fetus was found and removed from the pit by them. Rashi [s.v. she-chulda...] explains that the warren in which these animals live is usually more than one cubed tefach in volume (aprox. 512-729 cubed centimetres). We estimate that the animal dragged the fetus into its warren and, thus, the tum'a of the fetus could not defile the kohen even if he passed directly above it. If the warren was any smaller, and the kohen walked directly above it, he would become tamei. [See Mishna Ohalot 3:6]
C. Teisha tziburin shel matza [lines 32-39] The gemara discusses two cases whereby a mouse snatches an unidentified substance and brings it into a house that has already been checked for chametz. In both cases the mouse stole the substance from amongst nine piles of matza and one pile of chametz.
CASE #1 - KAVU'A - The mouse stole the substance directly from amongst the ten piles.
CASE #2 - PARISH - The substance was first separated (parish) from amongst the piles and only THEN stolen by the mouse.
In both cases the question under discussion is whether the house must be checked again or not. Did the mouse bring chametz or matza into the house.
The gemara quotes two analogous cases from Tractate Ketubot (15a) in order to solve the dilemma. In both cases a person found a piece of meat in a neighbourhood where there are nine stores (teisha chanuyot) which stock only kosher produce, and one store that stocks non-kosher produce.
CASE #1 - KAVU'A - The person found the meat in one of the shops but cannot remember which one.
CASE #2 - PARISH - The person found the meat AFTER it had left the vicinity of one of the shops (eg. It was lying on the road).
In both cases the question under discussion is whether or not one may eat the piece of meat. Do we assume that it came from one of the kosher shops or from the non-kosher store.
Case #1 in our gemara is compared with case #1 in Ketubot as in both instances the item under question was taken from a situation in which BOTH permissible substances (matza / kosher meat) AND non-permissible substances (chametz / non-kosher meat) were to be found. Under such circumstances we rule that the likelihood of the item under question being PERMISSIBLE is EQUAL to the chance of it being FORBIDDEN. Thus, one must do bedika again and it is forbidden for him to eat the meat.
Case #2 in our gemara is compared with case #2 in Ketubot as in both instances the item under question was first REMOVED from its original location BEFORE its status came into question. We apply the rule - kol de-parish me-ruba parish - whatever is separated is considered to have come from the majority. Thus, the house need NOT be re-checked and one MAY eat the meat.
For an explanation why the rulings in the two scenarios differ see this week's shiur by Dr. Moshe Koppel.