Context: a man is retelling the tale of his murder. He wants to prove he's not mad, only has exceptional senses due to his excitement. At this point, he's in the same room as his victim, listening to the victim's heartbeatIt grew louder, I say, louder every moment! — do you mark me well I have told you that I am nervous: so I am.
I don't get the phrase in bold. First, shouldn't there be a punctuation at the end of it? Like "do you mark me well? I have told you [...]"
Secondly, how should I interpret the meaning here? I can see two way to read into it: 1) "Do you hear me well?" and 2) "Do you judge me to be sound of mind now?" but which is it?
Source: The Tell-Tale Heart - Poe's Works | Edgar Allan Poe Museum