His glance fell upon the unopened phial on his dressing-table, and from his soul a silent thanksgiving rose to heaven that he had left that potion untasted. He realised that his own case differed from those of his predecessors in two particulars: He was actually in residence under Dr. Kassimere's roof and receiving treatment from the man's hands. No option was to be offered to _him_; the great experiment, the _Magnum Opus_, was to be performed without his consent! And Phryné!--Phryné, the other innocent victim of this fiend's lust for knowledge! The thought restored his courage. More than life itself depended upon his coolness and address; he must act, at once. The monstrous possibility hinted at by von Hohenheim--in his earliest published work, _Practica D. Theophrasti Paracelsi_, printed at Augsburg in 1529, was, in this hideous pamphlet, elaborated and brought within the bounds of practical experiment. He crept to the door, opened it, and stood listening intently. That silence which seemed like a palpable cloud--a cloud masking the presence of one who watched--lay over the house. Slowly he descended to the hall and dropped the horror which the evil genius of von Hohenheim had conceived, upon the spot where it had lain when his foot had discovered it. A creaking sound warned him of some one's approach, and he had barely time to slip behind some draperies ere a cowled figure bearing a lantern came out into the hall. It was Dr. Kassimere, wearing a loose gown having a monkish hood--and he was searching for something. Nothing in his experience--not the blood-lust seen in the eyes of men in battle--had prepared him for that which transfigured the face of Dr. Kassimere. The strange semblance of Thoth was there no more; it had given place to another, more active malevolence, to a sort of Satanic _eagerness_ indescribably terrifying; it was the face of one possessed. Like some bird of prey he pounced upon the book, thrust it into the pocket of his gown, and began furtively to retrace his steps. As he entered the big dining-room, Dillon was close upon his heels. Dr. Kassimere passed into the small room beyond and turned from thence into the library. Dillon, observing every precaution, followed. From the library the doctor entered the short, narrow passage leading to that quaint relic of bygone days and ways--the tiny chapel. At the entrance Dillon paused, watchful. Once, the man in the monkish robe turned, on the time-worn step of the altar, and looked back over his shoulder, revealing a face that might well have been that of Asmodeus himself.