[If] one slaughters [by cutting] one [of the organs] of a bird or both [organs] of an animal, his slaughtering is valid, and the greater part of one [organ] is tantamount to its entirety. R’ Yehudah says: Until he severs the veridin. [If he severs] half of one [organ] of a bird or one and a half [organs] of an animal, his slaughtering is invalid. [If he severs] the greater part of one [organ] of a bird or the greater part of both [organs] of an animal, his slaughtering is valid.