Perhaps ghost Moriarty's rude messages are like calisthenics and he's trying to build up enough psychic energy to burst one of jars in Holmes's ear collection. ^_____^

I'm wondering though if Moriarty will also try to raise a ghastly army consisting of the late unfortunates whose ears they are. But he'll find directing them difficult because every order will be met with: "I'm terribly sorry - what did you just say?" :P