I'm sure you've read this foreword to Spiritism and Common Sense, but this may give others leads to go on, such as the association with Hermann:
The author of this book, Rev. C. M. de Heredia, S.J., is so interesting a personality to meet, so fascinating when he, a Jesuit of dignity, is at play with his "ghosts" and ectoplasmic "spirits" that we give here, for the reader's benefit, a short account and description of him as taken from an interview, "The Secret of Spirit Trickery," printed in the Boston Sunday Post of March 14, 1920.
"Father Heredia is a rather short, stocky man, of Mexican birth, with a little forward thrust of his head and two of the most amazing blue eyes I ever saw. One moment they are looking at you, dreamily, quietly, almost sleepily. And the next they sharpen to a point and gaze through your skull at the wall behind you. The effect was most discomforting to skeptical me.
"For Father Heredia is a master of magic and mystification, a student in his youth of the great Herrmann, an artist supreme of the arts of the medium and clairvoyant. Yet, as he told me, his delving into the mystery of the shadowy world of the unseen is only a hobby. Primarily he is a studenta student of the modern languages and the classics, of philosophy and science. His father was a very rich Mexican, who had built a private theater for him and his brothers. When any celebrity came to Mexico, the father arranged to have him come and give a private performance in the boys' theater. Once Herrmann, the famous magician, was in Mexico, and performed before the boys in their theater. The father was so impressed at the magician's skill that he arranged to have him teach the boys his art. With this instruction by Herrmann began Father Heredia's interest in magic. All through his life he has followed the various tricks of the great magicians, many of whom have been personal acquaintances of his.
"When spiritism became popular, he perceived that most mediums were but unadept magicians, and devoted his spare time to disclosing many of their so-called mysterious powers."
P.J. Kenedy & Sons