Answer:
From this description of his study, I can tell that Dr. Heidegger is a medical doctor who engaged in the use of magical power to capture the spirit of the dead.
Step-by-step explanation:
This is true because we are told of a magical book which is found in his study.
The book is known to be a ponderous folio volume which was bound in black leather with silver clasps. The book had no letters on the back and no one knew the title. Such description reveals to us that the doctor uses magical powers in treating his patient.
The other account of the spirits of dead patients who dwelt within his verge also make us understand that the doctor uses sorcery or magic to trap his patients' spirit.
"Dr. Heidegger's Experiment" is actually a short story that is written by Nathaniel Hawthorne, an American author.