I had had allotted to me a number of slaves, and these I had won over by kindness and understanding until I knew that I had the full measure of their loyalty. They had no reason to love Ras Thavas and every reason to hate him; on the other hand they had no reason to hate me, and I saw to it that they had every reason to love me.

The result was that I had no difficulty in enlisting the services of a couple of them to spy upon Ras Thavas' spies, with the result that I was soon apprised that my suspicions were well founded-I was being constantly watched every minute that I was out of my apartments, but the spying did not come beyond my outer chamber walls. That was why I had been successful in reaching the vault in the manner that I had, the spies having assumed that I would leave my chamber only by its natural exit, had been content to guard that and permit my windows to go unwatched.

I think it was about two of our months that the spying continued and then my men reported that it seemed to have ceased entirely. All that time I was fretting at the delay, for I wanted to be about my plans which would have been absolutely impossible for me to carry out if I were being watched. I had spent the interval in studying the geography of the north-eastern Barsoomian hemisphere where my activities were to be carried on, and also in scanning a great number of case histories and inspecting the subjects to which they referred; but at last, with the removal of the spies, it began to look as though I might soon commence to put my plans in active operation.

Ras Thavas had for some time permitted me considerable freedom in independent investigation and experiment, and this I determined to take advantage of in every possible way that might forward my plans for the resurrection of Valla Dia. My study of the histories of many of the cases had been with the possibility in mind of discovering subjects that might be of assistance to me in my venture. Among those that had occupied my careful attention were, quite naturally, the cases with which I had been most familiar, namely: 378-J-493811-P, the red-man from whose vicious attack I had saved Ras Thavas upon the day of my advent upon Mars; and he whose brain had been divided with an ape.

The former, 378-J-493811-P, had been a native of Phundahl-a young warrior attached to the court of Xaxa, Jeddara of Phundahl-and a victim of assassination. His body had been purchased by a Phundahlian noble for the purpose, as Ras Thavas had narrated, of winning the favor of a young beauty. I felt that I might possibly enlist his services, but that would depend upon the extent of his loyalty towards Xaxa, which I could only determine by reviving and questioning him.

He whose brain had been divided with an ape had originated in Ptarth, which lay at a considerable distance to the west of Phundahl and a little south and about an equal distance from Duhor, which lay north and a little west of it. An inhabitant of Ptarth, I reasoned, would know much of the entire country included in the triangle formed by Phundahl, Ptarth and Duhor; the strength and ferocity of the great ape would prove of value in crossing beast-infested wastes; and I felt that I could hold forth sufficient promise to the human half of the great beast's brain, which really now dominated the creature, to win its support and loyalty. The third subject that I had tentatively selected had been a notorious Toonolian assassin, whose audacity, fearlessness and swordsmanship had won for him a reputation that had spread far beyond the boundaries of his country.

Ras Thavas, himself a Toonolian, had given me something of the history of this man whose grim calling is not without honor upon Barsoom, and which Gor Hajus had raised still higher in the esteem of his countrymen through the fact that he never struck down a woman or a good man and that he never struck from behind.

His killings were always the results of fair fights in which the victim had every opportunity to defend himself and slay his attacker; and he was famous for his loyalty to his friends. In fact this very loyalty had been a contributing factor in his downfall which had brought him to one of Ras Thavas' ersite slabs some years since, for he had earned the enmity of Vobis Kan, Jeddak of Toonol, through his refusal to assassinate a man who once had befriended Gor Hajus in some slight degree; following which Vobis Kan conceived the suspicion that Gor Hajus had him marked for slaying. The result was inevitable: Gor Hajus was arrested and condemned to death; immediately following the execution of the sentence, an agent of Ras Thavas had purchased the body.

These three, then, I had chosen to be my partners in my great adventure. It is true that I had not discussed the matter with any one of them, but my judgment assured me that I would have no difficulty in enlisting their services and loyalty in return for their total resurrection.

My first task lay in renewing the organs of 378-J-493811-P and of Gor Hajus, which had been injured by the wounds that had laid them low; the former requiring a new lung and the latter a new heart, his executioner having run him through with a short-sword. I hesitated to ask Ras Thavas' permission to experiment on these subjects for fear of the possibility of arousing his suspicions, in which event he would probably have them destroyed, and so I was forced to accomplish my designs by subterfuge and stealth. To this end I made it a practice for weeks to carry my regular laboratory work far into the night, often requiring the services of various assistants that all might become accustomed to the sight of me at work at unusual hours. In my selection of these assistants I made it a point to choose two of the very spies that Ras Thavas had set to watching me. While it was true that they were no longer employed in this particular service, I had hopes that they would carry word of my activities to their master; and I was careful to see that they received from me the proper suggestions that would mould their report in language far from harmful to me. By the merest suggestion I carried to them the idea that I worked thus late purely for the love of the work itself and the tremendous interest in it that Ras Thavas had awakened within my mind. Some nights I worked with assistants and as often I did not, but always I was careful to assure myself that the following morning those in the office were made aware that I had labored far into the preceding night.

This groundwork carefully prepared, I had comparatively little fear of the results of actual discovery when I set to work upon the warrior of Phundahl and the assassin of Toonol. I chose the former first. His lung was badly injured where my blade had passed through it, but from the laboratory where were kept fractional bodies I brought a perfect lung, with which I replaced the one that I had ruined. The work occupied but half the night. So anxious was I to complete my task that I immediately opened up the breast of Gor Hajus, for whom I had selected an unusually strong and powerful heart and by working rapidly I succeeded in completing the transference before dawn. Having known the nature of the wounds that had dispatched these two men, I had spent weeks in performing similar operations that I might perfect myself especially in this work; and having encountered no unusual pathological conditions in either subject, the work had progressed smoothly and with great rapidity. I had completed what I had feared would be the most difficult part of my task and now, having removed as far as possible all signs of the operation except the therapeutic tape which closed the incisions, I returned to my quarters for a few minutes of much-needed rest, praying that Ras Thavas would not by any chance examine either of the subjects upon which I had been working, although I had fortified myself against such a contingency by entering full details of the operation upon the history card of each subject that, in the event of discovery, any suspicion of ulterior motives upon my part might be allayed by my play of open frankness.

I arose at the usual time and went at once to Ras Thavas' apartment, where I was met with a bombshell that nearly wrecked my composure. He eyed me closely for a long minute before he spoke.

"You worked late last night, Vad Varo," he said.

"I often do," I replied, lightly; but my heart was heavy as a stone.

"And what might it have been that so occupied your interest?" he inquired.

I felt as a mouse with which the cat is playing. "I have been doing quite a little lung and heart transference of late," I replied, "and I became so engrossed with my work that I did not note the passage of time."

"I have known that you worked late at night. Do you think it wise?"

At that moment I felt that it had been very unwise, yet I assured him to the contrary.

"I was restless," he said. "I could not sleep and so I went to your quarters after midnight, but you were not there.