This book deals with the study of hysteria and demonism.

“The study of the malady under which these unfortunates suffer, in its present and past aspects, affords a new and instructive chapter in the history of human thought.

In pursuing the present inquiry, we shall endeavor first to describe the psychological symptoms of hysteria. The knowledge of this disease has received a remarkable development under the careful investigations of the physicians of the Salpetriere, and it may be that some of the facts they have discovered will interest persons who are not acquainted with medical science. We shall next inquire into the character of the demoniacal affections which were described in former centuries, and examine the strange succession of errors by which men were led to affirm that the devil took up his lodging in human bodies, and that it was necessary to burn him, to destroy those poor bodies which had become the receptacles and accomplices of malevolent spirits....

Some persons may be surprised to learn that hysterical patients are confined in the Salpetriere, for it has not been usual to regard hysteria as a grave disease necessitating or justifying seclusion. It is not always so grave”...