Dumbledore in CoS was Re: The Keeper of the Keys.

[pippin_999]

No: HPFGUIDX 113443

> SSSusan, who sure wishes someone would tackle her 
question of whether  Parseltongue is required to make the SINK 
open *or* the serpent DOOR  open *or* both....<

That one's easy. Harry tried English on the sink and nothing 
happened. It's also quite possible that the tiny snake scratched 
on the pipe is only visible in the presence of a Parselmouth. 

Dumbledore seems wary of drawing conclusions based on 
circumstantial evidence. Voldemort /Riddle is quite good at 
laying down misleading evidence and Dumbledore knows that , 
unlike Harry (and Snape) , who are always jumping to false 
conclusions. 

Dumbledore knows about Myrtle, but on the other hand he  can't 
hear Parseltongue as a voice so he doesn't know that the 
monster is moving through the walls. Ron, Hermione and 
Lockhart don't even notice the sound -- either Harry's ears are 
especially sensitive to parseltonge, or the hissing sounds like 
the background noises usual in the castle.

 If the petrification power of the basilisk is unknown to wizards, 
then no wizard had ever looked into a basilisk's eyes and lived to 
tell the tale. Myrtle had no idea what the big yellow eyes 
belonged to, and she also couldn't identify the boy she heard 
speaking. For all she knew, it *could* have been Hagrid.

If Hagrid had been willing to produce Aragog, then everybody 
might have seen that he didn't have big  yellow eyes. But Hagrid 
wouldn't turn over an interestin' creature.

Pippin