Hey, I just happened to see this discussion thread. Yes, it is possible to get a copy of this article. I compiled an anthology of some of the best articles from the history of WD and it's still for sale on Amazon. It's called Legends of Literature and The Detective in Fiction is one of the articles in there. It was transcribed from the original archives at WD, so it's accurate to the letter. Here's the link if you want it:
http://www.amazon.com/Legends-Litera...+of+literature