
This is a poster from the WPA urging people to save their own lives … by getting tested for a sexually transmitted disease. The geometry of the diagram in the center — the circle lined with Bauhaus-styled geometric human heads, divided into seven-and-three by inverted colors — seems to evoke the equipment used to conduct medical tests: the petri dish, the centrifuge.
I have no idea how syphilis tests were conducted in the first half of the 20th century, but the imagery just strikes me that way, intended or not.
I found this in the Library of Congress WPA Poster Collection.