I don't know what's going on here. Crazy Apple-selling man is becoming a Strangling Vampire, and the fellow he lured into his office is trying to get out the window? Normal guy is knocking on the window to let his confederates know they can enter the room and steal all the delicious apples? Who's Z?
As for Edwin Baird, he was the editor of "Detective Story Magazine." His tenure at the company was marked by failure at another title, Weird Tales; it lost a lot of money when he ran it, and the company offered the editorship to . . . H.P. Lovecraft.