J. Sheridan le Fanu 
In a Glass Darkly [PDF ebook] 

Whilst the greatest effort has been made to ensure the quality of this text, due to the historical nature of this content, in some rare cases there may be minor issues with legibility. It is related in a series of letters to his friend Professor Van Loo of Leyden. The professor was not a physician, but a chemist, and a man who read history and metaphysics and medicine, and had, in his day, written a play.