Zevachim 47: Where to Slaughter the Offerings, Vessels vs. Hands

Our daf completes perek IV and brings us to a new Mishna that introduces Perek V.  It teaches about the location and consumption of the offerings that are slaughtered.  We hear that there are halacha regarding the most sacred offerings - these include burnt, sin, guilt and communal peace offerings.  

The bull and goat offerings for Yom Kippur are slaughtered in the north, their blood is sprinkled between the staves of the Ark in the Holy of Holies and on the parochet, the curtain that separates that from the sanctuary, and on the golden altar/the inner altar.  The rabbis teach that any error disqualifies the offering.  The remaining blood is poured onto the western base of the external altar.  If there is an error here, the offering is not disqualified.  

Regarding bulls or goats that are burnt as sin offerings, the slaughter happens in the north of the Temple courtyard and the blood is collected in a service vessel in the north.  The blood is sprinkled on that same parochet and on the golden altar.  Mistakes disqualify these offerings.  The remaining blood is poured onto the western base of the external altar by a priest.  If this does not happen properly, the offering is not disqualified.  The bull and goat of Yom Kippur and the bull and goat that are burned are then burned in the place of the ashes.  This is located outside of Jerusalem.  

The Gemara suggests a principle taught by this Mishna: The collection of their blood in a service vessel is in the north of the Temple courtyard.  Why would this be ignored in the Mishna, which focuses on slaughter and sprinkling?  The rabbis decide that these offerings would include the guilt offering of a leper, for which the blood is collected in the hand, and thus these rituals could not be stated as a principle.  This would be the case even if the blood of a leper's guilt offering is collected in a service vessel.  

The rabbis argue about whether a vessel or simply the priest's body should collect this blood, for it is "put" onto the leper's ear, thumb and big toe - with the priest's own body. As they search for conformity and/or patterns, the rabbis question whether all of this blood should be collected by hand and not by service vessels at all.