FREE: Early 20th century Red Cross (?) Button/Pin

The listing, Early 20th century Red Cross (?) Button/Pin has ended.

This small button was probably worn to show that you donated blood for the war effort. The back of the pin shows a patent date of 1917 if my eyes aren't deceiving me, leading me to believe it may have been issued during or shortly after World War 1 (WWI). Due to the position of the pin itself I was unable to get my camera to focus in on the back. It reads Green Duck Co. Chicago with a picture of a duck above a patent date. There are a few other things I can't quite make out with the naked eye. If you have any additional information to add to it please feel free to comment. I'd love to learn more about it myself. Free shipping in the U.S.