"I certainly feel perfectly well in body," replied Mainwaring. "My mind is naturally much disturbed and upset, but I have neither ache nor pain, except----" Here he paused. "The word 'except' points to some slight discomfort, surely?" I replied, with eagerness. "Pray tell me exactly what you feel. Any clue, however slight, is most important." "I have a certain numbness of my right fore-arm and hand, but this is really not worth mentioning. I am absolutely strong and well. I _feel_ twenty-three." He sighed heavily as he spoke, and sinking into a chair, looked fixedly at me. "What do you consider the cause of my extraordinary condition?" he asked, abruptly. "The cause," I replied, "is either the plugging of an artery or the rupture of a small vessel in your brain. Thanks to the valuable researches of eminent men who have made the localization of cerebral functions the work of their lives, I am able to tell pretty readily in what portion of your brain the mischief lies." "How?" asked Mainwaring, starting forward in his chair and gazing at me with eyes of devouring interest. "You yourself have given me the clue," I answered, with a smile. "You tell me you have a distinct feeling of numbness in your right fore-arm and hand. We know that some of the highest cerebral centres are closely connected with the centres of the nerves of that limb. I can picture to myself--though, of course, I may be wrong--the exact spot where this lesion has taken place. It is certainly most important that something definite should be done to restore your memory and all it entails." "Then you will do that something?" exclaimed Mainwaring. "You cannot hesitate. You will not lose a moment in giving me the relief which I earnestly crave for." "I should like to consult Dr. Oliphant, the great brain specialist," I replied. Mainwaring sprang again to his feet. "No," he said, "that I cannot permit. He may say nothing can be done, and then you may have scruples with regard to the right of exposing my life to a certain risk. I will permit no consultation. If you know what is the matter with me, you can give me relief without seeking for further assistance. Do you think I value life under existing circumstances? Not that!" He flipped some imaginary substance away from him as he spoke with his finger and thumb. "I put myself absolutely into your hands, Dr. Halifax," he said, making an effort to restrain himself. "You say that an artery is plugged in my brain, or that there is the rupture of a small blood-vessel. You can surely do something to remove the obstruction?" "Yes," I said, "I can perform a certain operation, which I will shortly explain to you. I know you are a brave man; I do not, therefore, hesitate to tell you that the operation is of a very serious nature, also that there is a possibility of my being wrong with regard to the localization of the injury."