1. Rebbi Yehudah was aware of six cases in which Beis Shamai ruled leniently while Beis Hillel ruled stringently.
2. Beis Hillel: The blood of a Neveilah is Tamei if it is the amount of a Revi'is.
3. Rav Yehudah in the name of Rav: Hashem created everything for a reason.
4. Rebbi Zeira asked Rav Yehudah many questions about the nature of animals and various words.
5. Three animals grow stronger as they grow older.
A BIT MORE
1. One of these disputes was in the case of the blood of a Neveilah (an animal that did not die from slaughtering). Beis Shamai said that the blood is not Tamei, while Beis Hillel said that it is Tamei.
2. The reason for this is that it could harden into a k'Zayis of solid blood, which is the same amount required for the meat of a Neveilah to become Tamei and to cause Tum'ah.
3. For example, he says that Hashem created flies so that if one is stung by a hornet he can crush a fly and put it on the wound in order to heal it.
4. For example, Rebbi Zeira asked him to explain the nature of the word "Sudra," which refers to a headscarf worn by Torah scholars. Rav Yehudah explained that this word is an acronym for, "Sod Hashem l'Yerei'av" -- "the secret of Hashem is to those who fear Him."
5. They are a fish, snake, and a pig.