In breathless anxiety we listened, but all we could hear were the Professor's sighs of despair, which meant far more to Mrs. Tennison and myself than any of his words could convey. We knew that upon poor Gabrielle, the girl I loved with all my heart and soul, the deadly drug had done its work--and that she was, alas! incurable! Her case was hopeless, even in the hands of the one man in all Europe who knew the effects of orosin and had only in two cases effected cures. I looked at her mother in silence. She knew my thoughts, for tears were now coursing down her pale cheeks. Both of us knew the worst. Our journey had been in vain. That thought caused me to grit my teeth against De Gex and his unholy hirelings. I would follow and unmask them. I would avenge the innocent girl whom I loved so dearly, even though it should cost me my life! CHAPTER THE TWENTY-FOURTH YET ANOTHER MYSTERY The first week in August was unusually hot and dry in London. Gabrielle and Mrs. Tennison had remained in Lyons, for Professor Gourbeil had suggested that his patient should, as a desperate resource, remain under his treatment for a few weeks. He gave practically no hope of her recovery. The dose of orosin that had been administered was, he declared, a larger one than that which De Gex had introduced into my drink on that night of horrors. The effect upon me had been to muddle my brain so that I had accepted those Bank of England notes as bribe to assist the mystery-man of Europe in his foul and mysterious plot. My companion Harry Hambledon was still earning his guineas at Hammersmith Police Court, gradually establishing a reputation. He had bought a small two-seater car, and each Sunday he took Norah out for runs to the Hut at Wisley, to the Burford Bridge Hotel, where the genial Mr. Hunt--one of the last remaining Bohemians of the days of the Junior Garrick Club--welcomed them; to the Wooton Hatch, or up to those more pretentious and less comfortable hostelries on Hindhead. Motoring had roused a new interest in my friend. I loved the open road, but with the heavy expenses I had recently sustained I could not afford it. Besides, my firm had just secured a big electric lighting contract with the corporation of Chichester, and I was constantly travelling between that city and London, sometimes by rail and sometimes in Mr. Francis's car. I suppose I must have carried on my work satisfactorily after the generous leave the firm--one of those stately old-fashioned ones which have still survived the war--had accorded me. But my thoughts were ever of my beloved Gabrielle, the beautiful girl whom, though her mind was so strongly unbalanced, I yet loved with all the strength of my being.