Aaah! MvR's x-files are discovered! This would be the very best chance to ask him the most important questions of all: Where did the last shot come from? Was it Brown or not?
... more serious: A lot of pre-1940-photographs shows ghosts. The reason is simple. Consider the long exposure times the old films require. Exposure times up to 30 seconds on a cloudy day could be the norm on a older camera. And what happened if somebody on the picture has moved? He is looking like his own ghost on the print afterwarts. So keep MvR laying in peace and remind the older technology !