“Do as you are directed,” snapped Ras Thavas as he quit the room. I shrugged my shoulders. “There is nothing for it, then,” I said. “I might dispatch you all and escape,” mused the ape, aloud, “but you would have helped me. I could not kill one who would have befriended me—yet I shrink from the thought of another death. How long have I lain here?” I referred to the history of his case that had been brought and suspended at the head of the table. “Twelve years,” I told him. “And yet, why not?” he demanded of himself. “This man would slay me—why should I not slay him first.” “It would do you no good,” I assured him, “for you could never escape. Instead you would be really killed, dying a death from which Ras Thavas would probably think it not worth while ever to recall you, while I, who might find the opportunity at some later date and who have the inclination, would be dead at your hands and thus incapable of saving you.” I had been speaking in a low voice, close to his ear, that the attendants might not overhear me. The ape listened intently. “You will do as you suggest?” he asked. “At the first opportunity that presents itself,” I assured him. “Very well,” he said, “I will submit, trusting to you.” A half hour later both subjects had been returned to their shelves. CHAPTER IV THE COMPACT Days ran into weeks, weeks into months, as day by day I labored at the side of Ras Thavas, and more and more the old surgeon took me into his confidence, more and more he imparted to me the secrets of his skill and his profession. Gradually he permitted me to perform more and more important functions in the actual practice of his vast laboratory. I started transferring limbs from one subject to another, then internal organs of the digestive tract. Then he entrusted to me a complete operation upon a paying client. I removed the kidneys from a rich old man, replacing them with healthy ones from a young subject. The following day I gave a stunted child new thyroid glands. A week later I transferred two hearts and then, at last, came the great day for me—unassisted, with Ras Thavas standing silently beside me, I took the brain of an old man and transplanted it within the cranium of a youth.