"Women engaged in research work for the benefit of French soldiers"
Red Cross nurses, 1917.
This is right on the cusp of the Spanish flu pandemic of 1918. These nurses were about to get much busier. They may have even succumbed to the devastating infection themselves. Just some food for thought.
Public domain image, wikipedia commons
Original source: Nat’l Geographic Magazine., Vol 31, pg 327 (1917) (click this link and see what else was published in this issue!)