I noticed on the 1940 Famous American Scientist stamps that there is an image or symbol in the lower left corner that seems to relate to the work that each scientist is best known for (bird for Audobon, medical symbol for Walter Reed, etc.) I don't recognize the symbols on 876, (Luther Burbank, botanist) or 878, (Jane Addams, sociologist). Does anyone know what those symbols are or what they represent?
