"Miss H.W.S. From Christiansburg, Virginia."
She was Harriet Woods Eoff born 14th April 1893. On April 8, 1922 she married Harvard DeHart Castle in Manhattan and died in Rochester NY 11 Aug 1989. The writing below was the artist's note of her identity. The photo below is taken from a family photo with her parents and siblings from findagrave.com. I am hoping I may hear from members of her family with more biographic details.
Petite, pretty girl, pink cheeked with the freshness of her blossoming youth! She has to be the friend of all the soldiers, respected, waited for, taking on all the worries, easing the sorrows, relieving all the sufferings miraculously with her crystal-like laughter. She is not like many of our own nurses, symbols of courage and suffering: she has not, over years, known the anguish for loved ones, the long weeks without news, the horror of nights of bombardment on the ambulances. In the soldiers she treats, she has only seen victory; she has only been in this hard job a few months. This is what keeps her so youthful, so gay, so soft, like a spring rose.