What Cartoon Is This?

A reader named David Graves sent the following query:

I found your name through your blogs, but feel that my naive question might be appropriate for your readers.

I am the Process Architect at the Albert Einstein College of Medicine in New York City. My job is to re design operating processes, particularly when they are changed by installing computer automation. At a recent conference, my peers and I discussed our problem in explaining what we did.

I remember seeing a early black & white animated short that I felt captured the essence of the problems we all work on. I am trying to identify the short so I can acquire a copy.

In the short, a group of mice is taking mail from a basket and sorting it into a series of mail slots. On the back of the slots are a series of mail chutes that merge into one chute that drops the mail in a basket where a group of mice takes it and sorts it into a series of mail slots. On the back of the slots are a series of mail chutes that merge into one chute that .... and so on.

As you might image, Process Architects seek out and re-design that sort of process.

I am not a student of animation. I am seeking someone who is and can help steer me to the short. Can you tell where to look or how do the research that will lead me to the short?

I can't name the short, though I remember the gag. Most likely, it's a Terrytoon. If anyone can name the cartoon, please comment.