Oops, PS: Forgot to add, he would likely been wearing the khaki foreign service helmet, too, not the home service helmet in blue and with all the spangles. And no gloves or dress sword or belts. I'm still not sure about any weapon, still researching -- a sidearm for personal defense may or may not have been authorized for medical personnel on active service, or it may have been left up to the individual, or the preferences of field commanders for their troops. So Waton's revolver's history is up for ongoing study!
K