Chapter III. OUT OF PLAY
Do nothing that can harm your host! For the majority of the Hunter's kind even the desire to break that law never existed, since they lived on terms of the warmest friendship with the beings whose bodies harbored theirs. The few individuals who proved to be exceptions were regarded with the liveliest horror and detestation by their fellows. It was one of these whom the Hunter had been pursuing at the time of his crash on the earth; and that being, he well knew, must still be found-if only to protect this native race from the inroads of the irresponsible creature.
Do nothing that can harm your host! From the moment of the Hunter's arrival the swarming white cells in the boy's healthy blood had been aroused. He had avoided the most serious contacts with them up to now by keeping clear of the interiors of blood vessels, though there were enough of them wandering free in the lymphatics and connective tissue to be a nuisance. His body cells were not naturally immune to their powers of absorption, and only by constant evasive action had he been able to avoid serious damage to himself. He knew this could not go on indefinitely; for one thing, he must occasionally direct his attention to other matters, and, for another, the continuation of such a misunderstanding, whether he persevered in evasive action or began to fight back, would mean an increase in the number of white cells and probably some sort of illness to his host. Therefore, the leucocytes must be pacified. His race had, of course, worked out long since a general technique for solving this problem, but care still had to be taken in individual cases-particularly unfamiliar ones. By a trial-and-error process carried out with as much speed as was practical, the Hunter determined the nature of the chemical clue by which the white cells differentiated invading organisms from legitimate members of the human body; and after prolonged and still extremely careful effort he exposed every one of his cells to sources of the appropriate chemicals in his host's blood stream. A few molecules of the desired substance were absorbed on the surface of each cell, and this, to his relief, proved to be sufficient. The leucocytes ceased to bother him, and he could use the larger blood vessels safely as avenues of exploration for his questing pseudopoda.
Do nothing that can harm your host! He needed food as well as oxygen. He could have consumed with relish and satisfaction any of the various forms of tissue surrounding him, but the law made selection necessary. There were certainly intruding organisms in this body-besides himself-and they were the logical food source, for by consuming them he would be eliminating their menace to his host and thereby helping to earn his keep. Identifying them would be easy; anything a leukocyte attacked would be legitimate prey for the Hunter. Probably the local microbes would not keep him fed for long, small as his needs were, and it would also be necessary to tap the digestive tract at some point; but that need not cause damage, unless a slightly increased appetite on the part of the host came under that heading.
For many hours the cautious exploration and adjustment continued. The Hunter felt his host awaken and resume activity, but he made no effort to look outside. He had one problem which must be carefully and accurately solved; and, although his dodging the attentions of thousands of leucocytes at once, as he had done for a time, may seem evidence to the contrary, his power of attention was limited. That had simply been an automatic action roughly comparable to a man's carrying on a conversation while he climbs stairs.
Filaments of the Hunter's flesh, far finer than human neurons, gradually formed an all-inclusive network ' throughout Bob's body from head to toe; and through those threads the Hunter came gradually to know the purpose and customary uses of every muscle, gland, and sense organ in that body. Throughout this period most of his mass remained in the abdominal cavity, and it was more than seventy-two hours after his first intrusion that he felt secure enough in his position to pay attention once more to outside affairs.
As he had done with the shark, he began to fill the spaces between the boy's retinal cells with his own body substance. He was actually able to make better use of Bob's eyes than their proper owner could, for the human eyes see in maximum detail only those objects whose images fall within an area of retina less than a millimeter across. The Hunter could use the whole area on which the lens focused with reasonable sharpness, which was decidedly larger. In consequence, he could examine with Bob's eyes objects at which the boy was not looking directly. This was likely to be a help, since many of the things in which the hidden watcher was most interested would be too commonplace to the human being to attract his direct gaze.
The Hunter could hear dimly even within the human body, but he found it helpful to establish direct physical contact with the bones of the middle ear. Thus, hearing as well as seeing better than his host, he felt ready to investigate the planet on which chance had marooned him and his quarry. There was no further reason-he thought- for delay in searching for and destroying the criminal of his own race now free on the world. He began to look and listen.
The search itself he had never regarded as more than a routine job. He had had similar problems before. He had expected to look around from the vantage point of Bob's body until he found the others, leave and eliminate his opponent by standard means-regardless of the fact that all his equipment was at the bottom of the sea. He had had, in short, a viewpoint which is excusable in a space navigator but not in a detective: he had been regarding a planet as a small object and thinking his search was practically over when he had narrowed it down to one world.
He was rudely jolted out of this attitude as he took his first look around since meeting Bob Kinnaird. The picture that fell on their common retinas was that of the interior of a cylindrical object vaguely suggestive of his own space ship. It was filled with several rows of seats, most of them occupied by human beings. Beside the watcher was a window through which Bob was looking at the moment; and the suspicion that had entered the Hunter's mind was instantly confirmed by the view through that window. They were on board an aircraft, traveling at a considerable altitude with a speed and in a direction which the alien was in no position to estimate. Start looking for his quarry? He must first look for the right continent!
The flight lasted for several hours and had probably already consumed several. The Hunter quickly gave up the attempt to memorize landmarks over which they passed. One or two of them did stick in his mind and might give a clue to direction if he could ever identify them later; but he put little trust in this possibility. He must keep track of time rather than position, and when he was more familiar with human ways find out where his host had been at the time of his own intrusion.
The view itself, though, was interesting, even if the landmarks were lacking. It was a beautiful planet, from his alien viewpoint; mountains and plains, rivers and lakes, forests and prairies were all visible at various times, now clearly through miles of crystal atmosphere and now in glimpses between billowing clouds of water vapor. The machine he rode was also worthy of attention; from Robert's window he could not see very much of it, but that little told him a great deal. A portion of a metal wing was visible, bearing attachments which evidently contained engines, as rapidly rotating air foils were visible ahead of them. Since the craft was presumably symmetrical, the Hunter decided there must be at least four of these engines. He could not tell with accuracy how much of then- energy was wasted in heat and sound-for one thing, he suspected that the cabin in which he rode was quite effectively sound-proofed. The machine as a whole, however, suggested that this race had evidently attained a considerable degree of mechanical advancement, and a new idea blossomed from that: might he not attempt to enter into communication with this being which was his host and secure its active co-operation in his, search? It was a point well worth considering.