The instructions on the back of the envelope are more detailed than is usual for this period, and detail how to make flat fell seams. They also instruct that the hems are to be folded to and sewn on the outside. I wonder why this is.
I'm curious to know how the process of home sewing for the Red Cross worked during WWI. Did one purchase the pattern from the Red Cross, or did stores carry them? Were there special prices on the fabric? Did the maker sew on the Red Cross Emblem, or did Red Cross volunteers do this? Were the shirts quality checked and bundled by the local Red Cross chapters?