Brian, a friend at work saw this in an antique store in New Orleans and took this picture for me.
After mulling it over for a week and talking to two other historians of medicine who write on comics, I called up and ordered it. I haven't printed it yet, but flopping and inverting the picture lets you see it:
So it's a printing block for a fundraising ad campaign for the March of Dimes to conquer polio. Pretty neat especially the iron lung in the center. I'm going to try to ink it and print it, and we'll see what results I get. Perhaps we can make prints as write-in prizes!