Aurora listened to Professor Lafay and jotted down notes as she did so...
Right, now for the good bit. She picked up her valerian and her Salamander blood and held each over the cauldron. Right.
One drop Valerian.
One drop Salamander blood.
One Valerian.
One Salamander.
Valerian.
Salamander.
And so on until she had added ten drops of each.