Thanks for this interesting post on Percy Dana. So many great boxing photos from this man around the turn of the 20th Century. It appears that you found some source material on him through the San Francisco Library Historical Collection. Since I live here in SF, I will make it a goal of mine to get in to the library and hopefully view some of their collection in person. I found a short piece on him at Foundsf.org, and I've added the address/link below.
http://www.foundsf.org/index.php?tit...g_Photographer